Abstract: To study the variation of winter accumulated temperature in semi-arid area of Longdong and its influence on winter wheat, by means of Mann-Kendell statistical test and Pearson correlation analysis, the winter accumulated temperature and the development period of winter wheat were analyzed. The results showed that: (1) the winter accumulated temperature had a rising trend year by year in the past 36 years; Mann- Kendall mutation test indicated that 1990 was the mutation year of winter accumulated temperature; Morlet wavelet analysis indicated that the winter accumulated temperature had a most significant periodic variation of 30-35 years; (2) by analyzing the developmental characteristics of winter wheat, we found that the development of winter wheat was delayed in tillering stage, while that of other stages, like sowing, seedling, trefoil, overwintering, etc. were ahead of schedule; the correlation analysis of winter wheat development period and accumulated temperature showed that the correlation coefficient was negative, indicating that most of the development stages were advanced by 1-5 days; in the year with higher winter temperature, the winter wheat development stages were generally ahead by 4-14 days; (3) characteristics analysis of phenology interval showed that in the stage of sowing to seedling, sowing to tillering, sowing to over wintering, sowing to re-greening and sowing to heading, the phenology interval was prolonged; while in the stage of sowing to trefoil, sowing to heading, sowing to jointing, sowing to flowering and sowing to maturity, the phenology interval was shortened.