[Objectives] It is of great significance to study the differences of niches among species and the mechanism of how to achieve coexistence in ecological research and the formulation of scientific conservation decisions. Sable (Martes zibellina), Yellow-throated Marten (M. flavigula) and Siberian Weasel (Mustela sibirica) are three small and medium-sized weasel species in the same area of the Qingsong forest. The purpose of this study is to better protect the three species of animals by ascertaining their spatio-temporal niche differences. [Methods] From November 2019 to November 2021, 41 infrared cameras were deployed to monitor the activity rhythm and spatial distribution of three species of animals in Qingsong forest area of Shulan City, Jilin Province, and 10 transects were set to assist the investigation of their distribution. Fig. 1 shows the geographic location and elevation range of the study area. Fig. 2a shows the locations of the infrared camera in the study area, and Fig. 2b shows the locations of the line transect and the sites of the three animals obtained from the line transect survey. Based on the data obtained from the survey, we calculated the circadian and daily activity rhythms of the three species, and predicted the habitats of the three species. The MaxEnt was used to model the habitats of the three species. We randomly set 25% of active sites as test data, 75% of active sites for model construction, check Linear features and Hinge features for feature crosses, set the regularization multiplier to 2.6, repeat the cross validate procedures for 10 times, and finally select the average of 10 runs as the modeling result of MaxEnt. The geographical distribution overlap of these three species was calculated by using ENMTools 1.3. The kernel density method was used to model the daily activity rhythm. The above analysis was performed in MaxEnt 3.4.1, ENMTools 1.3 and R 3.6.3. [Results] There were a total of 29 971 camera working days captured 99 independent valid records of Sable, 81 independent valid records of Yellow-throated Marten, and 163 independent effective records of Siberian Weasel; the line transect survey collected 7 active sites of Sable, 17 active sites of Yellow-throated Marten, and 29 active sites of Siberian Weasel. The results show that Sable is nocturnal (daytime-and-night relative abundance index, DRAI = 70.7%). Yellow-throated Marten is diurnal (DRAI = 90.1%). Siberian Weasel is nocturnal (DRAI = 72.4%) (Fig. 3). The activity time of Sable and Siberian Weasel is similar, but the activity peaks are staggered (Sable’s activity peaks at 21:00 daily and Siberian Weasel’s activity peaks at 19:00 and 2:00, their activity rhythm coefficient of overlap Δ = 0.864) (Fig. 4). Yellow-throated Marten’s activity peaks at 8:00 and 16:00, which are staggered with the activity time of the Sable (daily activity rhythm coefficient of overlap Δ = 0.330) (Fig. 5). Yellow-throated Marten and Siberian Weasel are staggered in time (daily activity rhythm coefficient of overlap Δ = 0.282) (Fig. 6). According to the results of MaxEnt modeling, the habitat area of Sable, Yellow-throated Marten and Siberian Weasel avoided each other in habitat distribution (Fig. 7). The habitats of Sable and Yellow-throated Marten are partly overlapped (Niche overlap Hellinger’s-based I = 0.809, Schoener’s D = 0.531), but they avoid Siberian Weasel (Niche overlay Hellinger’s-based I = 0.590, Schoener’s D = 0.307). The habitats of Yellow-throated Marten and Siberian Weasel have less overlap in areas close to human disturbance (Niche overlap Hellinger’s-based I = 0.752, Schoener’s D = 0.456) (Table 1). According to Jackknife test, we can know the importance of environmental variables. Altitude (52.2%) was the main environmental variable affecting the distribution of Sable’s habitat. Followed by distance to rivers (17.9%), distance to evergreen coniferous forest (12.0%) and distance to residents (5.8%). The main environmental variables affecting the distribution of Yellow-throated Marten habitats are distance to residents (60.3%), followed by distance to deciduous broad-leaved forest (16.5%), distance to deciduous coniferous forest (6.5%) and distance to rivers (12.8%), and the main environmental variable affecting the distribution of Siberian Weasel’s habitat was slope (34.3%). Followed by distance to residents (28.3%), distance to evergreen coniferous forest (13.1%) and distance to deciduous broad (8.0%) (Table 2). Because Sable mainly inhabits coniferous forests in high altitude areas of steep and dangerously steep grade far away from residential areas and near water sources; Yellow-throated Marten is widely distributed in coniferous forests at middle and high altitudes far from residential areas and close to water sources; Siberian Weasel is mainly distributed in areas close to residential areas and cultivated lands with gentle slopes, preferring to live in deciduous broad-leaved forests and avoiding evergreen coniferous forests (Table 3). [Conclusion] Sable, Yellow-throated Marten and Siberian Weasel had differentiated their spatio-temporal niches by choosing different daily activity rhythms and different habitats, thus achieving coexistence in the same area of Shulan Qingsong forest.