In-situ evaluation of crack generation using acoustic emission (AE) technique as a non-destructive testing method was applied during laser cladding of WC-Co cemented carbide via a multi-beam laser metal deposition (LMD) system. Especially, this study aims to investigate relationships between the laser output and the number of cracks generated in beads of WC-12mass%Co cemented carbide cladded by the LMD system. The number of cracks was evaluated using an AE sensor attached to a substrate. The number of cracks was also evaluated from SEM images of beads. By comparing these results, problems in the both evaluation methods for crack generation in laser cladding were discussed.