In order to realize the laser quenching heat treatment of the cam , according to the three problems of the cam getting uniform hardened layer, combining with movement forms of laser processing machines, the mathematical model of relative movement is established about laser beam and the cam surface in the laser quenching process with combining the motion form of laser processing machine, the theoretic analysis and algorithm research are carried out of laser head's movement, and the formulas of X、ω、B three-axis motion are derived. The result shows that the laser quenching heat treatment of the cam can be controlled feasibly, and it has laid a theoretical foundation for the process of complex parts.