Abstract: In this paper, 70 representative meteorological stations were selected over Shanxi province, the absolute value of negative accumulated temperature was computed and its changing trend was analyzed by means of Modern climate statistical methods. The results showed that during the recent 43a,the descending trend of the absolute value of annual negative accumulated temperature and days of daily average temperature<0℃ was significantly，their abrupt change happened in 1987 and 1995 respectively, too. They were relatively low after 1986 and 1995 with a decreasing by 103.4℃ and 10d on average respectively，even warm winter mainly occurred. As a result, the winter wheat cultivable area expanded, in the mean time, it reduced the mortality rate of winter sickness egg (cocoon) and increased its survival quantity, so it is easy to cause plant diseases, increases the preventing and controlling difficult. There are both advantages and disadvantages of change negative accumulated temperature to winter wheat in Shanxi province.