Abstract: Sexual dimorphism and reproductive output is an important part of life history of Eremias argus. In June and August 2013,We collected 95 pregnant females and 38(18♂20♀) adult E. argus from a population in Ordos of Inner Mongolia (northern China) in order to study sexual dimorphism and female reproductive output. The examined morphological traits included body mass, snout-vent length, head length，head height, head width, brachium length, ante-brachium length, wrist-finger length(the length of wrist to the tip of the forth finger), thigh length, shank length, ankle-toe length(the length of ankle to the tip of the forth toe), abdomen length and tail length; The pregnant females were feed in the terrarium until parturition, mother body mass and eggs were weighed, clutch size was recorded by us . The data of morphological traits were analyzed by the one-way ANOVA and ANCOVA, and then female reproductive traits were outcomes of the regressive analysis and the partial correlative analysis. The results showed that E. argus is a sexually dimorphic species, and it specifically presents: the head size, limb length and tail length are larger in males and abdomen length of females is larger (Table1). The smallest reproductive female in our sample was 44.0 mm snout-vent length (SVL). It occurred between 4 June and 15 July, when egg-laying came; and clutch size is varied from 2 to 5 eggs (mean = 2.9). Clutch size (P= 0.043) and clutch mass (P= 0.026) were positively related to female SVL, and relative clutch mass (P= 0.001) was negatively related to female SVL (Fig.1); clutch size (P= 0.000) and average egg weight (P= 0.000) were positively related to clutch mass, and clutch size was negatively related to average egg weight (P= 0.200). Key words: Eremias argus；Sexual dimorphism；Female reproduction