A new filter strategy for harmonic elimination is introduced in this paper. The proposed approach eliminates all harmonics component from the signal (current or voltage) and it requires only knowledge of fundamental frequency of the signal. The proposed active series filter eliminates undesirable harmonics from periodic signal. This filter utilizes an integrator, amplifier, multipliers and subtraction circuit. Adaptation process exactly match amplitude and phase of fundamental frequency component and the outputs of the filter is a harmonics replica and are subtracted from the original periodic signal waveform to eliminate them. The bipolar waveforms are roughly analyzed and considered case of square wave pattern which contain all odd harmonics. The simulation results show that the method can effectively eliminate undesirable harmonics and result in low total harmonic distortion (THD).