Method for improving heat resistance of polyurethane resin optical material

The invention belongs to the technical field of optical resin, and particularly relates to a method for improving the heat resistance of a polyurethane resin optical material. The method provided by the invention mainly comprises the steps of polymerizing dihydric alcohol or dihydric sulfur alcohol and dihydric olefin into a low polymer according to a certain ratio, adding the low polymer serving as a modifying agent into a prepolymer of poly thiocarbamic acid ester optical resin prepared from polybasic sulfur alcohol and dihydric isocyanate, and then performing defoaming, casting and heating curing, so that the heat resistance of a resin lens is improved to 108 to 120 DEG C, and a relatively high impact strength is kept.