Method for cleaning dust on surfaces of precision instruments

The invention relates to a method for cleaning dust on the surfaces of precision instruments. The method includes filling tanks with liquid nitrogen; cleaning the dust by the aid of the liquid nitrogen (with the dosage of 500-800ml/m ); wiping the surfaces of the precision instruments by the aid of cotton balls with ethyl alcohol or ethyl ether; further cleaning the dust by the aid of the liquid nitrogen (with the dosage of 200-400ml/m ); wiping the surfaces of the precision instruments again by the aid of cotton balls with ethyl alcohol or ethyl ether. The method has the advantages that the surface dust cleaning time can be greatly shortened, the precision, the sensitivity, the light transmittance and the stability of the precision instruments can keep unchanged; the method is wide in application range, low in cost and simple in operation.