A method of testing a performance of a HGA including a magnetic head and a micro-actuator for precisely positioning the magnetic head with respect to a magnetic medium is disclosed. The key of the method is to obtain three track center values under conditions of no driving the micro-actuator, driving the micro-actuator in a positive direction using an operating DC voltage, and driving the micro-actuator in a negative direction using the operating DC voltage respectively, and finally do calculation of the three track center values, thus successfully obtains the displacement performance of the micro-actuator in a simple way. The method is capable of testing the HGA's performance under lower operating voltage by moving the slider by a predetermined distance toward an off-track direction, which accordingly assists to identify three track center values and thereby ensures the method an accurate measurement.