In order to clarify the phenological process of flowering and leaf expanding in peach, and the effects of chilling and heat requirement differences between floral and leaf buds on the phenological process, we first evaluated the chilling and heat requirements of floral and leaf buds of 257 peach germplasms, and investigated the full bloom date and leaf expanding date, then according to the chilling requirement of floral buds, the materials were classified into 4 types of very low, low, medium and high chilling requirement, respectively, and finally the phenological process of different types of peach in different years, as well as chilling and heat requirement differences of each phenological process, were systematically discussed. The results showed that peach with very low chilling and low chilling requirements had 3 kinds of phenological process, including “flowering before leaf expanding”, “simultaneous flowering and leaf expanding” and “leaf expanding before flowering”. The phenological process of the same germplasm varied in different years, and the patterns of chilling and heat requirement differences were complex and varied accordingly. Peach with medium chilling and high chilling requirements had only 1 kind of phenological process, which was “flowering before leaf expanding”, and the patterns of chilling and heat requirement differences were simple and unvaried. The phenological process of peach floral and leaf were related to patterns of chilling and heat requirement differences, and mainly depended on the difference of heat requirement. Regardless of the chilling requirement of the floral bud, when the heat requirement of floral bud was less than that of leaf bud, the phenological process was “flowering before leaf expanding”; when the heat requirement of floral and leaf buds was equal, the phenological process was “simultaneous flowering and leaf expanding”; when the heat requirement of floral bud was greater than that of leaf bud, the phenological process was “leaf expanding before flowering”. The results indicated that the heat requirement difference of the floral bud and leaf bud was chiefly responsible for the different and variable phenological process of peach.