The resource allocation patterns of dioecious plants often show significant gender dimorphism. but whether there are differences in leaf photosynthetic and leaf functional traits between dioecious plants is still uncertain, as well as the relationship with development stages is not clear. Clarifying the above-mentioned problems can further understand the physiological and ecological characteristics of dioecious plants, and provide a theoretical basis for understanding the influence mechanism of gender effects on the growth and development of sexual dimorphic plants. In our research, the photosynthetic characteristics and leaf functional traits between gender in dioecious species Fraxinus velutina Torr. were measured at three different development stages (Fruit setting stage, Fast-growing stage, and Fruit ripening stage). A two-way ANOVA was used to analyze the gender differences in photosynthetic capacity and leaf functional traits of male and female plants among different development stages. Pearson was used to test the correlation between leaf functional traits of male and female plants, and a standardized major axis regression (SMA) was used to understand the correlation between net photosynthetic rate and leaf functional traits of different gender plants. The results showed that gender and development stages significantly affected the photosynthetic capacity and leaf functional traits in F. velutina Torr. Generally speaking, compared with female trees, male ones showed higher net photosynthetic rate (Pn), specific leaf area (SLA), chlorophyll content (Chl) and leaf nitrogen content (LNC) at fruit setting stage and fruit ripening stage, and lower Pn, SLA, and Chl in the fruit growing stage. There was a significant positive correlation between Pn and SLA, Chl and LNC in male and female (P<0.05), and the slope of SLA vs. Pn was higher in male trees than female trees (P<0.05). The relationship between Chl vs. Pn was not significant between the genders (P>0.05) and the slope of LNC vs. Pn of male trees was higher than that of female trees (P<0.05). The results of SMA model indicated that the light energy utilization efficiency and photosynthetic nitrogen utilization efficiency were higher in male trees than those in female trees, and female trees would use more biomass and nitrogen for non-photosynthetic processes, but no significant differences were found in light absorption rate between genders. The results of this study showed that the life history strategies of male and female individuals of F. velutina Torr. were different, and there existed significant sex dimorphism in photosynthetic traits and leaf functional traits at three different development stages.