Abstract: Researches on the laser deposition repair of aircraft vertical tail beam with mis-machined damage were investigated. According to the mechanical characteristics while its serving, the samples of mechanical properties were designed and the tensile properties at room temperature of laser deposition repaired sample and substrate sample were analyzed. Besides, microstructure characteristic, microhardness distribution were also analyzed. The results showed that there was a dense metallurgical bond between repaired zone and substrate. And the laser repaired zone experienced a continuous microstructural transition from duplex microstructure with equiaxial and lamellar / in substrate to the epitaxial coarser columnar with basket weave / through heat-affected zone. And the repaired zone was characterized by a fine / lamella microstructure without defects. Distribution of microhardness from substrate to repaired zone showed an increasing trend, and the average microhardness of repaired zone increased by 12%. Whether the tensile specimens with holes or not, laser repaired samples tensile strength were slightly higher than substrates, but the ductility were lower than substrate. Based on the optimized process parameters, the causes of edge collapse defect on the repaired sample were analyzed at the same time and the ideas to reduce defects were given to enhance the deposition quality.