The ionosphere contamination imposing on the high frequency (HF) radar echoes has to be suppressed since it severely degrades the detection performance of HF radar. In this paper, the mechanism of the ionosphere contamination from the ionosphere distortion is exposed for the first time by analyzing the course of HF radar signal processing. According to the high spatial correlativity of the ionosphere contamination, then the rank one phase error estimation (ROPE) autofocus method in imaging radar is suitably modified and applied to the ionosphere decontamination of HF radar echoes. Finally the simulation examples are presented and the excellent performance of this approach is demonstrated when the ionosphere slowly distorts.