Abstract: According to characteristics of high frequency surface wave radar range spectrum, a new method of interference detection is proposed by using correspondence analysis and cluster analysis. The correspondence analysis separates the characteristic factors of range spectrum in time domain and range domain. The cluster analysis classifies the characteristic factors. And then automatic identify the radio frequency interference, ionospheric clutter, signal and noise. By using this method, three month radio frequency interference and ionospheric clutter characteristics from measured data is attained.