Abstract: Based on the data of the daily mean air temperature and the minimum soil surface temperature of 70 meteorological stations in Shanxi Province from 1970 to 2012, the heat indices of agricultural resources including accumulated temperatures above 0 ℃ and 10 ℃, the average temperature in July and the annual frostfree duration were calculated. Their variation trends and mutation were analyzed by using linear regression and accumulated anomaly methods. The effect of agricultural heat resource on crop producing area was analyzed. The results showed that the accumulated temperatures for above 0 ℃ and 10 ℃ had increased significantly at a rate of about 64.8 and 57.9 ℃·d·（10 a）^-1, respectively (P<0.001). The average temperature in July and the annual frostfree duration had significantly increased at a rate of about 0.3 ℃·（10 a）^-1 and 5.9 d·（10 a）^-1, respectively. The increasing ranges of heat resource indices had different spatial distribution patterns in Shanxi Province. The accumulated temperatures were greater in the west than that in the east. The average temperature in July was greater in middle and north than that in the south. The annual frostfree duration was greater in the middle than that in the south and north. The accumulated temperatures above 0 ℃ and 10 ℃ showed a clear mutation in 1996, so were the average temperature in July in 1993 and the annual frostfree duration in 1997. Compared to the time before mutation, the accumulated temperatures above 0 ℃ and 10 ℃ increased by 219.4 ℃·d and 196.7 ℃·d, respectively, the average temperature in July by 0.8 ℃ and the annual frostfree duration by 15 d. As a result, hot crop cultivable area and warm crop cultivable area were expanded northward, while the mild crop cultivable area, cool crop cultivable area, cold crop cultivable area and alpine plants area were shrunk. The maximum expansion was of the warm crop cultivable area (by 175.7%). The maximum shrinkage was of the cold area (by 87.9 %). The cultivable area of cotton was expanded by 1.7×10⁶ hm² (53.5%), and that of potato was shrunk by 8.9×10⁶ hm² (30.5%).