Distyly is a floral polymorphism, characterized by a reciprocal positioning between stigmas and anthers in different individuals. In this study, we employed Forsythia suspensa to explore divergence in functional gender of two floral morphs and evolutionary significance of the distyly, by determining characteristics of mating system and comparing ovule number, pollen dry weight, pollen viability and longevity between two sexual morphs. The results showed that the species has heteromorphic incompatibility system, with the extremely low fruit set by selfing and intramorphpollination. The ovule number was (26.86 ± 0.37) in the longstyled morph, significantly higher than that in the shortstyled morph. The dry weight of pollen per flower was (0.47 ± 0.02) mg in longstyled morph, significantly lower than (0.60 ± 0.02) mg of the shortstyled one. The content of water in anther was significantly different between two morphs, which in shortstyled was significantly higher than in longstyled. Overall, pollen viability of the shortstyled form was significantly lower than that in the longstyled, so did pollen longevity. In conclusion, it was indicated that the relatively reproductive input in two sexual functions differed between two morphs. The longstyled was femalebiased, realizing its fitness to larger extent by ovules, whereas the shortstyled was malebiased, realizing the fitness largely by exporting pollen.