本文分析了苹果梨树短、长枝叶片在花芽分化期核糖核酸酶活性的变化规律。结果表明：核糖核酸酶活性在花芽分化前期逐渐增高并达到最大值，生理分化期逐渐下降，进入形态分化期后开始上升，到花原基大量分化时出现一个峰值。指出核糖核酸酶活性在花芽分化期起了一定的促进作用。为进一步探讨遗传物质对果树花芽分化的作用及二者的关系研究提供参考数据。 In this paper, the changes of ribonuclease activity of apple and pear branches in flower bud differentiation were analyzed. The results showed that the ribonuclease activity increased gradually and reached the maximum in the early stage of flower bud differentiation, decreased gradually in physiological differentiation stage, then began to rise after entering into morphological differentiation stage, and reached a peak when the flower primordium was heavily differentiated. It is pointed out that the activity of ribonuclease plays a promoting role in flower bud differentiation. In order to further explore the role of genetic material on the flower bud differentiation of fruit trees and the relationship between the two to provide reference data.