The present invention provides an adjusting method of a tilt meter. First, multiple holding signals of the same direction output from a tilt sensor, respectively, are differentiated to obtain at least a tilt signal. Then, a first judging step is performed to determine whether the tilt signal is in a predetermined range or not and a rough tuning step is executed to limit the voltage of the tilt signal in the predetermined range. Then, the voltage of the tilt signal in the predetermined range is amplified by a predetermined multiple. Afterwards, a second judging step is performed to determine whether the tilt signal after amplification is equal to a level voltage or not and a delicate tuning step is proceeded to adjust the voltage of the tilt signal to become equal to the level voltage.