Abstract: Based on the phenological observation data and temperature data in 2020, this paper studies preliminarily the effect of environment temperature change on the fruit expansion of Cangxi red kiwifruit and its growth law. The results show that: Cangxi ecological red kiwifruits begin to bear fruit as well as enter the young fruit stage in late April and mature in mid-late September; it takes about 150 days from fruit bearing to harvest, which belongs to late-maturing red kiwifruits. The local fruit growth curve is a three-step process of “fast-faster-slow”. Combined with the analysis of temperature factors in the same period, the growth rate of fruit transverse and longitudinal diameter is closely related to the diurnal temperature variation. When the diurnal temperature variation is large enough, it can promote the development of fruit, and the greater the variation, the better the promotion effect.