Pilot Induced Oscillation (PIO) is a safety issue which is concerned by airworthiness authorities. Firstly, I and II PIO susceptibility of a civil aircraft are calculated and analyzed by engineering prediction criteria. Secondly, according to AC25-7A, flight test methods and evaluation criteria of PIO are proposed. Finally, confirm whether it has PIO susceptibility by analysis of flight data and pilot comments. The flight results show that there is no any PIO susceptibility in flight test period and the civil aircraft meets the minimum allowable HQRM requirements. Furthermore, the flight results are consistent with prediction.