Abstract: In this paper, the variations of agricultural climate resources during the crop growth season (May to September) are studied by using the daily climatic data of 28 weather stations in Heilongjiang province during 1961 to 2010, with the application of Mann-Kendall mutation detection and trend coefficient analysis. And the precipitation feature especially in time and intensity distribution were analyzed by using precipitation concentration degree (PCD) and precipitation concentration period (PCP) methods. The results showed that in the recent 50 years the sunshine duration had a decreasing tendency, with an average of every 10 years to reduce 88 hours, and the stabilizing mutationtook place in 1980.Agricultural heat resource increased significantly with the increase of mean temperature (P<0.01), the minimum temperature increase was the main contributor to the warming. The mean temperature duringcrop growing season had a mutation in 1996 which had a nearly 10 years delay than that of the annual mean temperature. The accumulated temperature ≥10℃ and the duration of it also increased significantly（P<0.01）, however, the inter annual change of the starting day and the ending day of accumulated temperature ≥10℃ was large. Agricultural precipitation resource had a decrease tendency, which had a mutation in 1997, with the decrement of average4.0mm of every 10 years. The interannual variation of precipitation distribution was more obvious as the precipitations amount became big. The precipitation days of light rain and moderate rain decreased significantly(P<0.01), while the days of heavy rain and rainstorm increased, the average growth rate of them were 0.5 and 0.45d per 10 years respectively. The precipitations concentration period (PCP) took place in late July. The precipitations concentratordegree (PCD) increased with the level of rainfall amount, the higher the level of rainfall amount, the biggerthe PCD. The PCDs of heavy rain and rainstorm were 57.7% and 68.7% respectively. Too concentrated extreme precipitation was unfavorable for crops to utilize and may cause local flood.

Key words: Heilongjiang province, Crop growth season, Climate resource, Characteristics change, Linearity trend, Mann-Kendall test