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The presence of oxygen inhibition effect in radical photopolymerization leads to incomplete curing in the surfaces and affects the final performance of cured material. In this work, the insensitivity of thiol-acrylate system to oxygen was introduced into the upconversion particles assisted near-infrared photopolymerization (UCAP) to overcome the oxygen inhibition effect of acrylate system. The effects of the UCPs concentration, the structure and content of thiol monomers on the oxygen inhibition degree were systematically studied by combining thiols with (meth) acrylate monomers. The ATR-FTIR were used to characterize the polymerization kinetics of monocomponent (meth) acrylate and thiol-acrylate systems in UCAP. The double bond conversion at different depths of the cured material was characterized by Confocal Raman Microscopy. The results show that in the mixed system of secondary mercaptan PE-1 and acrylate monomer EM2261 with 2. Owt% UCPs and 50%-SH molarity, the maximum double bond conversion of 82% was obtained on the surface and over 90% in the deep layer, the oxygen inhibition degree of the surface layer were effectively reduced. [ABSTRACT FROM AUTHOR]