Abstract: This experiment use the spring rape,green rapeo-46 as the tested materials.Through cutting the leaves of this kind of rape in its period of flowering, we try to find the effect on the differentiation and formation on the organ of sink by reducing the source.The research shows that： cutting the leaves of rape which means reducing the source area,affected the accumulation of photosynthetic product,which directly cause the height of the plant reduce,stems become thinner, branching angles decreases, silique number decreased,thousand seed weight increased,silique size,PPA and SNPA decreased,biological yield and economic yield decreased.And the research also shows that cutting the leaf have bigger influence on the branching yield than cutting the Lord inflorescence.and cutting more reducin~ more,also cutting small leaves have bigger influence than cutting the large leaves.