A calibration method for calibrating a simulated motion trace is disclosed. The calibration method includes measuring an acceleration, an inclination angle and an azimuth of a terminal of a sports equipment, computing the simulated motion trace of the terminal according to the acceleration, the inclination angle and the azimuth, estimating a trace surface on which the simulated motion trace locates according to the simulated motion trace, computing a rotational angle between the trace surface and a display surface, projecting the simulated motion trace onto the display surface according to the rotational angle to generate a calibrated trace, and displaying the calibrated trace.