A method and a system for machining a work piece by a machining tool are provided. The method includes relatively moving the machining tool against the work piece to apply machining feeds therebetween. The contact points at the work piece are arranged on the area of the work piece to be machined, and the contact points at the machining tool form a curve on the machining tool surface. The system includes a manipulator, a machining tool and a controller being adapted for controlling the manipulator to operate the machining tool according to the method as above. With this solution, the system can generate wave paths of a machining tool, so as to extend the life of the tool and ensure the processing quality.