Abstract: In this paper, Ni60 alloy powders were used to improve the fatigue strength of cruciform joints of Q235B through modification of spray fusing. Test results showed that the section shape of welded joints can be improved by flame spraying. High cycle fatigue test results showed that 2×10⁶ cycles offset fatigue strength of the welded joints spray fused by Ni60 increased by 64.5%. The thermal stress was simulated by the finite element(ANSYS12.0) based on spraying parameters. Simulation results show that, the residual stress of substrate material and coating layer is still tensile stress and compared with as-welded joints, the magnitude of tensile stress decreases slightly. The residual stress of as-welded and coating surface is about 238 MPa and 182 MPa respectively. Thus, the residual stress is decreased by 24% after spray fusing.