Bite force of animals can reflect the ability of anti-predation, and attracting the opposite sex. For lizards, there is usually a significant linear relationship between head shape of individuals and their bite force. We performed the head morphometric analysis using species Trapelus sanguinolenta (♀13, ♂11) collected in Tukai Desert of Huocheng County, western Xinjiang, in July 2018. We measured the bite force of each individuals by a membrane pressure tester to analyze the relationship of the bite force with the sexual dimorphism in head. Then we employed the analysis of variance (ANOVA), principal component analysis, Akaike information model and stepwise regression analysis to analyze the difference in the head shape and bite force between females and males of the lizard species. The results showed that no significant intraspecific difference in the head morphological indexes for this lizard (Table 1), as well as no significant difference was found in the bite force between females and males. However, there was a difference of bite force in slope coefficients of head depth between males and females (Fig. 2). The bite force of the males increased faster with the head depth than the females did. The results of Principal component analysis and Akaike information model showed that head length, head width and lower jaw length were important factors affecting the bite force (Fig. 1, Table 2). Stepwise regression analysis revealed that the bite force was mainly affected by head width (Table 3). The results indicated that the bite force of T. sanguinolenta is affected by the size of the head. No significant intraspecific difference in the bite force is consistent with the morphological characteristics of the head, which may indicate an adaptation of this species to the shrub habitat. Specifically, it is the result of a trade-off between head size and movement balance.