Cleaning method of optical substrate for laser thin-film element

The invention relates to a cleaning method of an optical substrate for a laser thin-film element. The cleaning method includes the specific methods: using a cotton swab dipped with acetone for wiping the optical substrate until the surface of the substrate is free of macroscopic contaminants under the irradiation of an incandescent lamp; placing the wiped substrate in alkaline solution of a first tank, and respectively performing ultrasonic cleaning for the substrate successively by different frequencies; placing the substrate in a second tank, and using deionized water for spraying; and placing the substrate in deionized water of a third tank, successively subjecting the substrate to ultrasonic with different frequencies for 3-6 minutes, observing the surface cleanliness of the substrate under the incandescent lamp, and after the surface of the substrate is free of macroscopic particles, placing the substrate in deionized water of a fourth tank for slow lifting under ultrasonic of 80KHz, and drying the lifted substrate by hot blowing so that the required product is obtained. A cleaning processing and surface detection are combined together, a wiping method, a chemical cleaning method and an ultrasonic cleaning method are combined for comprehensive application, so that high cleaning efficiency and optimal cleaning effect less in damage to the smooth surface of the substrate are achieved.