Abstract:[Objectives] Bdelloid rotifers are microscopic aquatic invertebrate animals and widespread freshwater and soil inhabitants, being found from poles to equator and from shores to high mountains. They are able to use the thin water film surrounding soil particles, lichens or mosses and play a key role in microbial food webs. Exclusively parthenogenesis, horizontal gene transfer and exceptional resistance to extreme environments through anhydrobiosis make bdelloid rotifers ideal model organism. However, the taxonomy, diversity and distribution of bdelloid rotifers are poorly studied in Asia, especially in China, and the information on their occurrence is scant and insufficient. [Methods] In order to investigate the species diversity of bdelloid rotifers in Guangdong Province, we conducted a survey of these animals in Baiyun Mountain and Huolu Mountain. Samples were collected from water, mosses and leaf litter (Table 1). The water samples were obtained by a plankton net with 30 μm mesh size. Samples from mosses and leaf litter were extracted by washing the substrate with distilled water, then examined using microscope immediately. All living bdelloid rotifers were recorded and photographed using a digital camera. Rotifer body dimensions were measured from screenshots of digital videos. However, we only measured the size of one rotifer from each new record due to the rarity of these species. Photos and digital screenshots from videos were both used for species identification and illustrations. Mode pattern of measurement system for bdelloid rotifers were given in Fig. 1. [Results] One new record family of bdelloid rotifer in China: Philodinavidae Harring, 1913, two new record genera: Henoceros Milne, 1916, Didymodactylos Milne, 1916, and six new record species: H. caudatus Hauer, 1937, H. falcatus (Milne, 1916), D. carnosus Milne, 1916, Otostephanos regalis Milne, 1916, Macrotrachela kallosoma (Schulte, 1954) and Habrotrocha longiceps (Murray, 1906) were recorded. The morphological and structural characteristics of the six new record species are described by pictures and mode pattern, and their ecological information is also presented (Fig. 2﹣7). Notably, it is the second time that H. caudatus has been found in China since the original description in 1937, which indicated its limited biogeographic distribution and rarity; H. falcatus was confirmed widespread in Africa, Europe and Asia. All Philodinavidae species are considered to be lotic species. Compared with the original description, the spur of D. carnosus observed in this study is slightly wider, with no difference in other morphological characteristics. The morphology of O. regalis in our study differs from that in original description, with many short bristles on the neck. M. kallosoma has been recorded in many parts of Europe and is commonly found in water habitat. H. longiceps protects itself by building a nest around its body. This species is rare outside Europe. [Conclusion] At present, considering the results of the present study, there are a sum of 99 species of bdelloid rotifers that belonging to 13 genera and 4 families have been recorded in China. However, there is still one family (Coronistomidae) and seven genera (Abrochtha Bryce, 1910, Zelinkiella Harring, 1913, Embata Bryce, 1910, Philodinavus Harring, 1913, Anomopus Piovanelli, 1903, Ceratotrocha Bryce, 1910, Coronistomus ?rstan, 2021) not being discovered in China. China has a vast territory and diverse habitats, we suggest to implement a variety of experimental methods to broaden the scope and depth of survey on the bdelloid rotifers, and enrich the species diversity of bdelloid rotifers in China, and further explore the ecological value of bdelloid rotifer.