A method for adjusting a frequency response parameter of a machine tool and a system using the same are provided. The method includes the following steps. Firstly, an actual frequency sweep is performed on the machine tool to acquire an original system closed loop data of the machine tool. Then, an original system open loop transfer function of the original system closed loop data is acquired. Then, a speed optimization procedure is executed to determine an optimized speed parameter. Then, a speed optimized open loop transfer function corresponding to a speed optimized close loop transfer function is acquired. Then, a filter transfer function of a filter is determined. Then, a filter optimization procedure is executed.