[Objectives] Measures of animal performance can be used to quantify the ability of an individual to perform specific activities, and the maximum dive duration for voluntary diving is an important measure of dive performance. In addition, repeatability is the most widely used metric for assessing the consistency of behavior. The Crocodile Lizard (Shinisaurus crocodilurus) is an endangered semi-aquatic lizard and often uses diving behavior as a strategy to avoid enemies. In this study, we took captive-reared Crocodile Lizards as studying objects to test how their maximum dive duration and its influencing factors. [Methods] From July 2021 until August 2021, captive-reared Crocodile Lizards in Daguishan Nature Reserve, Guangxi, China, were artificially disturbed (not directly touched) and their corresponding diving behaviors were recorded on camera. We read the maximum diving duration and behavioral characteristics (whether they move and close to stones) of captive-reared Crocodile Lizards through video. The influencing factors of diving behavior include morphological characteristics (variables in Table 1), behavioral characteristics and environmental factors (dive time, ambient temperature and water temperature). A total of 61 captive-reared Crocodile Lizards (25 sub-adults, 19 females, 17 males) participated in the analysis. Then, to test the repeatability of the diving duration of Crocodile Lizard, we tested for the presence of correlations within an individual for dive duration across the three dive trials using Pearson's correlation coefficients and adjusted using sequential Bonferroni adjustments. More, a general linear model was also used to analyze whether environmental factors (air temperature and water temperature) had an effect on the maximum dive duration of Crocodile Lizards, with the dive time period used as a covariate. Based on the results of the analysis of environmental factors, we employed the analysis of variance (ANOVA) to analyze the relationship of behavioral characteristics, groupings (sub-adult, male and female) with the maximum dive duration. Finally, we employed the one-dimensional linear regression and stepwise regression analysis to analyze the relationship of morphological characteristics with the maximum dive duration of these 61 Crocodile Lizards. [Results] Results indicated that the diving behaviors of Crocodile Lizards were repeatable (n = 61, r2-3 = 0.495, r1-3 = 0.563, r1-2 = 0.530, all P < 0.001), the maximum diving duration range shown in Table 2. No difference in maximum dive duration between sex and ages of the Crocodile Lizards (F2, 58 = 0.747, P = 0.478). The maximum dive duration of Crocodile Lizards was not affected by the behaviors during diving (to move or not to move: F1, 59 = 0.465, P = 0.498; is it near the stones: F1, 59 = 0.516, P = 0.475). Moreover, temperature (air temperature: n = 61, r =﹣0.239, t =﹣1.298, P = 0.199; water temperature: n = 61, r =﹣0.172, t =﹣0.048, P = 0.962) also did not affect the maximum dive duration of the Crocodile Lizards. We found that maximum dive duration in the Crocodile Lizards was negatively correlated with tail length and tail volume, but positively correlated with tail loss (Fig. 1, Table 3). [Conclusion] Our results suggest that the diving performance of captive-reared Crocodile Lizards is influenced by tail characteristics and that a trade-off between diving performance and swimming performance may have occurred.