本发明提供一种聚氨酯光学树脂制备方法及其应用，所述制备方法包括将包含异氰酸酯和多元硫醇化合物的原料组合物通过聚合反应得到所述聚氨酯光学树脂，所述原料组合物中所用的异氰酸酯中存在的异氰酸酯的二聚体结构聚合物的含量控制为≤4wt％，优选≤3wt％，进一步优选为≤2.5wt％，更优选为≤1.6wt％。本发明提供的聚氨酯光学树脂制备方法能够良好的制造聚氨酯光学树脂且能有效降低制品光学形变发生率。

The invention provides a preparation method and application of a polyurethane optical resin. The preparation method comprises the step of carrying out a polymerization reaction on a raw material composition containing isocyanate and a polythiol compound to obtain the polyurethane optical resin, wherein the content of the dimer structure polymer of isocyanate present in isocyanate used in the raw material composition is controlled to be less than or equal to 4 wt%, preferably less than or equal to 3 wt%, further preferably less than or equal to 2.5 wt%, and more preferably less than or equal to1.6 wt%. According to the preparation method of the polyurethane optical resin, the polyurethane optical resin can be well manufactured, and the optical deformation occurrence rate of products can beeffectively reduced.