Abstract: Based on the meteorological observation data from 14 agro meteorological stations from 1971 to 2010,the temporal and spatial distribution of diurnal temperature range (DTR) in main grain production areas of Heilongjiang province,and the relationship between DTR and maize,rice yield were analyzed.The results showed that DTR decreased from 1971 to 2010,and the max decrease found in spring,followed by farming period and summer,the min decrease found in autumn.The spatial variation of DTR no obvious along the latitude or longitude in whole province,but DTR in mountain areas was higher than that in plain areas.The DTR dropped quickly in west and slowly in east,so it decreased quickly in Songnen plain and Mudanjiang region,but slowly in Sanjiang plain.Besides,the variation of DTR had local differences in farming seasons.Correlation between DTR and maize or rice yield was significant in different time scale from 64% stations,the DTR reducing was favorable to crop yield in the farming period,spring and summer,while the DTR increasing in autumn had a positive effect on crop yield.

Key words: 〖WT5HZ〗Key words：〖WT5BZ〗Heilongjiang province, Diurnal temperature range (DTR), Maize, Rice, Yield