The cleaning effect, cleaning mechanism and surface performance under different frequencies were investigated. The optimal frequency can be obtained by theoretical calculation. Solid fiber laser was used in the experiment. The cleaning frequency single factor parameter was controlled. The surface oxide layer of Q235 low carbon structural steel was taken as an example for the cleaning experiment. The results showed that the surface of the sample was the best after being cleaned at 350 kHz frequency. When the frequency was 250 kHz, the surface roughness of the sample reached a minimum value of 2.572 μm, and the matrix was slightly damaged. When the frequency was 150 kHz, the friction coefficient of the sample reached a maximum value of 0.3905 and the matrix damage was also the maximum. The surface oxide layer cleaning mechanism of Q235 was ablative and sputtering. With the increase of frequency, the ablative effect decreased gradually but the sputtering effect increased gradually. When the frequency was 550 kHz, the lowest proportion of ablation was 68%. When the frequency was 150 kHz, the sample surface was secondary oxidized. The matrix surface was seriously damaged, and the surface roughness was the largest. In the range of 250~550 kHz, the surface roughness of the sample increased with the increase of frequency. With the increase of frequency, the overall tendency of the surface friction coefficient decreased after the laser dry cleaning. When the frequency was 150 kHz, the laser energy density was the highest and the laser enhancement was the most obvious. The residual stress of the sample cleaning surface decreased with increasing frequency. With the laser of a frequency of 350 kHz, the electrochemical corrosion performance of the surface was the best. If it is higher or lower than this frequency, the electrochemical corrosion performance of the surface will decrease after the cleaning. In laser dry cleaning, frequency as an important parameter has a significant influence on the cleaning effect, cleaning mechanism and surface performance.