The work aims to investigate the influence of different pre-fabricated groove angles on the microstructure and properties of laser additive remanufactured IN718 alloy. The pre-fabricated grooves were repaired layer by layer by laser additive remanufacturing technology. The microstructure and fracture morphology of the remanufactured samples were observed by optical microscope and scanning electron microscopy, respectively. The hardness, residual stress and tensile mechanical properties of the remanufactured samples were measured by Vickers hardness tester, residual stress tester and universal tensile tester, respectively. When the pre-fabricated groove angle was greater than 130°, the additive remanufactured samples without structural defects and good forming quality could be obtained. When the pre-fabricated groove angle was lower than 110°, the fusion interface might be poorly fused, and cracking might occur on the repaired area. The pre-fabricated larger groove angle could obtain remanufactured samples with finer structure and more uniform hardness distribution during laser additive remanufacturing experiment, and the larger groove angle could reduce the residual stress of the remanufactured sample matrix. Increasing the groove angle could significantly improve the plasticity of the remanufactured samples. As the groove angle decreased, the mechanical properties of the remanufactured samples deteriorated. During the laser additive remanufacturing process, it is not suitable to pre-fabricate too small groove angle, the groove with larger groove angle should be pre-fabricated according to the damage condition, which is beneficial to improving the uniformity and mechanical properties of the remanufactured sample.