The change of Endogenous hormonein leaf during the period of flower bud differentiation of apricot was studied.The results showed that the flower physiological differentiation needed the high contain of ABA,the ratio of DHZR to IAA and low IAA,the ratio of DHZR to ABA content.The con-tent of ABA continues in low level during the period of flower bud morphological differentiation.Meanwhile,increasing the value of IAA and the ratio of IAA to ABA was required during male flower bud differentiation in Apricot.