Solve the problem of the steady transition in CNC machine speed in the high speed machining during start and stop. Based on the linear interpolation algorithm of double-axis and two dimensional, a new control method for double-axis stepper motor accelerating and decelerating at the same time was put forward, and the hardware on FPGA was realized. By two stepper motors directed to X and Y controlled through a set of circular distributor and driving-circuit, a transition may be steady. The simulation result gave good control effect and showed the effectiveness of this algorithm.