A system for acceleration adjustment of machine tool at rapid traverse includes a signal measurement module, a signal judgment module and an acceleration optimization module. The machine tool has a servo motor and a working platform. The signal measurement module measures signals while the servo motor drives the working platform from a first specific position to a second specific position, or from the second specific position back to the first specific position. The signal judgment module judges whether the actual maximum current value of the motor is equal to the manufacturer's specification according to the signals; and if negative, the acceleration optimization module calculates and optimizes an axial acceleration till an optimal value is achieved. Then, a curve smoothing time of the optimal acceleration is calculated and optimized by the acceleration optimization module. In addition, a method for acceleration adjustment of machine tool at rapid traverse is provided.