To improve the efficiency of acquisition, one vibrator group starts sweeping without waiting for the previous group’s sweep to terminate, this is called “slip sweep”. But this arrangement will generate harmonic noise in the previous shot record from the next shot and result in seismic data quality reduction. The authors analyzed the sweep signal in time-frequency domain and designed a harmonic separated operator by utilizing the correlated characteristics of harmonic distortion and fundamental signal. By applying this harmonic separated operator to the uncorrelated raw seismic data, high-order harmonic noise will be obtained. The results shows that the effect of this high-order harmonic noise attenuation method is effective.