The invention belongs to the technical field of diamond saw blade welding, and particularly relates to a laser automatic welding machine for diamond saw blades. The machine comprises a machine body, a saw blade absorbing grabbing system, a base body rotary indexing system, a tool bit conveying grabbing system, a welding clamping assembling system and a laser welding light path system; saw blade base bodies and tool bits are grabbed and subject to alignment pairing through the saw blade absorbing grabbing system and the tool bit conveying grabbing system, clamping positioning is completed through the welding clamping assembling system, and welding is carried out through the laser welding light path system; after the tool bits are welded, the saw blade base bodies are rotated to the next welding station through the base body rotating indexing system until the tool bits on the saw blade base bodies are welded, and the finished product saw blades are conveyed and discharged to the storing position through the saw blade absorbing grabbing system. The machine is a producing machining device which is high in speed, free of contact and small in deformation, large-batch production can be achieved, the welding strength is high, in the cutting and using process, the tooth disengaging phenomenon is avoided, and use safety of the machine is greatly improved.