The invention relates to a tiny-crack-free curved glass hot-wire cutting method based on a thermal shield membrane. The method particularly includes the steps of: 1) building a hot-wire cutting device, fixing the curved glass on a mold of the hot-wire cutting device, and marking a cutting position where a crack is preformed on the surface of the glass; 2) symmetrically arranging the thermal shield membrane at two sides of the cutting position of the preformed crack on the curved glass; 3) moving the hot wire to right over the preformed crack on the curved glass, heating the hot wire to a certain temperature and controlling the hot wire to move in a predetermined trace and cutting the curved glass to form the crack. Compared with the prior art, a temperature field, which is generated by the hot wire on the glass surface, is controlled by the thermal shield membrane, so that the temperature field on the glass surface is stably changed and is not liable to be influenced due to external environment factors. The formed crack, compared with a crack formed by a common thermal resistance wire, has higher straightness, thus satisfying demands of cutting glass lens in higher precision.