Objective To explore the boys' and girls' explicit and implicit attitude towards body figures. Methods A total of 101 boys and girls in the first grade from one senior middle school participated in the study. The negative physical self scale （NPSS） and extrinsic affective Simon task （EAST） were used to investigate explicit and attitude of body images.  Results Firstly, there were significant gender differences on explicit attitude of body figures. The scores of boys' negative attitude towards fatness were significantly lower than those of girls, while the scores of girls' negative attitude towards thinness were significantly lower than those of boys. Secondly, in the experiment of implicit attitude, the main effects of compatibility were significant and the main effects of gender were marginally significant. Conclusion ① The explicit attitudes of body images had significant gender differences. The boys were found to prefer fat figures, but the girls preferred thin figures. ② In implicit attitude, both boys and girls took same attitudes to self-body image and the opposite gender body image, and they tended to link fat figures with negative emotion and thin figures with positive emotion.