For the laser cladding of WC doped Ni-based alloy on 20Cr2NiSiW substrate, the stress status of cladding layer are analyzed .The thermal residual stress of laser cladding layer without preheating is 700 MPa, and phase changing residual stress is 850 MPa. The stress distribution of cladding layer can be ameliorate with preheating before cladding and thermal retardation after cladding. The part of thermal stress is relieved and the residual stress of phase changing is descend. Although the cladding layer still is compressive stress and the heating affected zone is stretching stress, the thermal stress peak is decrease to 510 MPa and shifted from face to intermediate section of cladding layer. The interface peak of stretching stress of phase changing is relieved, and satisfaction of stress status of cladding layer is obtained. On the non preheating cladding layer, the eutectic austenite dendrite growth is along the opposite direction of temperature gradient beginning from interface to face of cladding layer. On the preheating cladding layer, the eutectic austenite dendrite growth is changed from beginning the perpendicular border of cladding pool to intermediate section of layer.