In order to meet the demand of multi-wavelength output in laser cleaning, an optical path control system which can realize four wavelengths laser output alternately in a laser cleaning machine is designed. Based on the nonlinear effect of BBO crystal, the motion parts in light path are switched through the main controller program, and four-wavelength output is realized in the same optical path system. By using two sets of vibrating mirror system at the laser output terminal, scanning output of each wavelength laser beam is realized, which expands the use range of laser cleaning machine. Experiment results show that the designed optical control system is stable and reliable, simple and easy to be realized.