Abstract: In order to understand the flowering biological characteristics of Forsythia mandschurica cultivated in Harbin, the floral organ characteristics and flowering phenology of F.mandschurica cultivated for quite a few years in Heilongjiang University were observed. The results illustrated that the buds emerged in early April, and the flowering period of it began in mid-April. The flowering period of single plant was 19-27 days, and that of single flower was 11-14 days. Before winter, flower bud differentiation was finished, and calyxes, petals, stamens and pistils were obviously visible. The pollen grains of stamen had been formed, and ovule within ovary was developed. The calyx was 4, the stamen anthers were fitted, the stigma was bificated, and the axial placenta was occupied. Overall, the buds of F.mandschurica showed that the buds of it differentiated earlier, the duration of flowering period was longer, and the flowers were bright.