Abstract: In order to explore flower buds growth and development of Forsythia suspensa heterostyly（long style type and short style type）and its pollination habits，we took advantage of paraffin section and stereomicroscope to observe flower buds differentiation process，and conducted pollination tests of F. suspensa. In the middle of May，we started to take materials when F. suspensa began to sprout young shoots，and the flower buds of heterostyly with lengths of 1，2，3，4，5 and 6 mm were used for paraffin section. From August to the second year before flowering，we observed and photographed the flower buds structure of F. suspensa. We did self-crossing，intramorph and intermorph mating test of heterostyly in the flowering. The results showed that flower buds differentiation and flower organ growth and development process included flower buds differentiation，dormancy，flower buds germination and expansion，flower buds scale abscission phase，squaring period，dew corolla phase，flowering stage. The flower buds differentiation process can be divided into these stages：initial differentiation，sepal primordium differentiation，petal primordium differentiation，stamen and pistil primordium differentiation，pistil and stamen formation，pollen grains formation. One year before flowering，there was no significant difference in flower buds differentiation and development of heterostyly. In the flowering year，after the flower buds outer scales fell off，long style type elongated and exceeded the stamen height，and the filament began to develop，while short style type was basically developed，the filament grew rapidly over style height. The results of pollination experiments showed that the seed setting rate of intermorph mating was more than 50%，intramorph mating was slightly more than 20% and self-crossing was about 5%，indicating the characteristics of self-incompatibility.

Key words: Forsythia suspensa, heterostyly, floral buds growth and development, pollination habit