Abstract: With proper simplifications and assumptions, 3D finite element model of thermal-mechanical field was developed based on ANSYS software to numerically simulate distribution of temperature and stress fields upon solidification after thermally spraying nickel on steel substrate.The evolution of temperature and stress with time at some important spots in the coating was obtained and the effect of coating thickness on the stress in the interface between the coating and substrate was analyzed.The results show that the temperature in the coating gradually decreased from the center to the border.The residual stress on the coating was compressive,and increased with the increase of coating thickness.