This paper presents a method to improve the harmonic measurement and compensation performance of an active power filter (APF) by applying an individual Park Transform and designing an appropriate LPF. This method can improve accuracy, reliability and response speed more than applying a conventional LPF without continuously needing one cycle of data when measuring by using individual Park Transform.The simulation results show that when an appropriate LPF(butterworth filter) is designed using the proposed method, the voltage ripple is reduced compared to when a conventional LPF is used, and the response speed can be improved by at least 18.22 [%]. Accuracy is also validated by agreement with conventional FFT-based measurement results. The proposed method is expected to be applicable to harmonic-compensating devices such as APFs and hybrid filters, as well as harmonic measurement and power analysis equipment.