Abstract: Using the NCEP/NCAR reanalyzed monthly data and monthly temperature from 15 meteorological stations of Heilongjiang Province from 1954 to 2012 and adopting the methods, such as correlation, trend, composite analysis, the key zones influencing summer temperature of Heilongjiang Province are found from correlogram of summer temperature with 500 hPa height field and sea level pressure field with 200 hPa zonal wind field. Based on these key zones, the key factors and indices are objectively defined. The preliminary results of the analysis show that, Ural Mountain high, Baikal Lake high and Okhotsk high influence the temperature through teleconnection, but the impact from northeast cold vortex is direct. Correlation coefficient between northeast cold vortex and summer temperature is 0.87 and the consistent rate is 95%, so we can conclude that northeast cold vortex has influenced the summer temperature directly; in addition, North Pacific sea-level pressure index in summer and westerlies shear index are very important systems influencing the summer temperature. Combination of numerical models output, key factors and indexes of this study can be used to predict the summer temperatures of Heilongjiang Province.