Abstract: Ionospheric phase contamination makes the echo spectrum of over the horizon radar (OTHR) propagating through the ionosphere spread, which affects the target detection performance of the radar. In recent years, a method based on piecewise polynomial phase modeling was developed to solve the problem of ionospheric phase contamination. Aiming at the encountered problem when apply the method to processing actual data, more suitable piecewise principle is discussed and an improved order-selecting method is proposed, which simplifies the complexity of the method and increases the computation rate. By applying it to processing actual data, the effectiveness of the method is verified and it is indicated that the method is more suitable to the engineering practice application.