Abstract: Based on the differential equations for heat balance control of transient temperature field with phase changing and heat source,the finite element programs were developed by adopting the grid segmentation of the mixture cell in space domain and by the mixture solution of the finite difference format segmentation in time domain.The numerical calculation of temperature field was carried out,on the basis of measuring the heat of hydration.The active factors and the formation of strength of freezed cast-in-place pile in permafrost of Heilongjiang Province were analyzed.It was indicated that the temperature of cast-in-place concrete and the heat of hydration of different additive had great influence on temperature of soil around the pile.Suggestions for cast-in-place concrete pile in permafrost of Mohe County were: admixture composed of pulverized fuel ash,silica powder,early-strength ening agent and water-reducing agent;temperature of cast-in-place concrete controlled at 5℃.Therefore the formation time of bearing capacity would be greatly shortened.