The variation in spring leaf unfolding date of woody plants is commonly influenced by air temperature in a prior period, which is called the temperature-relevant period (TRP). The shifts in start and length of TRP reflect how climate warming influence plants development. Using the phenological data from China Phenological Observation Network, our study analyzes the changes in start, end, length, and temperature-phenophase relationship (R_TRP) of TRP for 162 woody plants in 8 representative sites of eastern China during 1980-2018. The following results are drawn. (1) Compared with temperate sites, the mean start and length of TRP in subtropical sites are 43 days earlier and 13 days longer, respectively, which is related to the higher forcing requirement and relative slower temperature accumulation rate during TRP of plants in subtropics. (2) The starts of TRP have changed slightly in the northern part of temperate zone (Harbin and Mudanjiang), but have significantly advanced in the southern part (Beijing, Xi'an and Minqin) at 0.41-0.53 d/a. In subtropical sites, except for Guilin, the proportion of plants showing an extended TRP and a shortened TRP is similar in the other sites. It suggests that the effect of climate warming on the chilling process in different sites not only depends on the magnitude of warming, but also is closely related to the background climatic conditions of the sites. (3) The start and end of TRP for tree species is 6.49 days and 3.92 days later than that of shrubs on average, respectively. The length of TRP for trees is a little shorter than that of shrubs. This is related to the opportunistic survival strategies adopted by shrubs, while trees are more conservative in spring to reduce frost risk. (4) In general, the species with an early leaf unfolding date exhibit an early start and a longer length of TRP, as well as a stronger R_TRP in both temperate and subtropical sites. The results can provide scientific reference for studies about the influence of climate change on plant phenology and the development of phenological models.