In the present paper,1Cr12Ni3MoVN alloy was repaired by laser repair (LR) with 1Cr11Ni2W2MoV. A very good metallurgical bond between the repaired zone and the substrate was achieved. The microstructure of the laser repaired zone (LRZ) is composed by martensite and tempered martensite,and a quenching phenomenon was observed in heat affected zone (HAZ). Micro-hardness values decreased from LRZ to substrate zone (SZ),the maximum value happened in the HAZ close to the melting line. The results of room temperature tensile tests show that the strength of LRZ is 1280-1380 MPa,while the strength of laser repaired sample is 965-980 MPa. Fractures were observed on casting substrate during tensile test.