Abstract: Flower bud of Zao Xing Yan Peach selected from June to October in 2000 is processed by scanning electron microscope and paraffin-cut section and the flower-bud differentiation is observed systemically. The results show as follows. In protected conditions the time of flower bud differentiation of peach is from middle July to the end of September. The majority of flower bud primordia are formed from end of July to middle September. What’ more, there are close relation between flower bud differentiation and temperature, different types of shoots, different parts of same shoot and accumulation of nutrient substance.