Abstract： Purpose: This study aims to determine vitamin D concentrations in the vitreous and serum, as well as the expression levels of NLRP3 inflammasome pathway in the vitreous of patients with proliferative diabetic retinopathy (PDR). In addition, we investigated the possible correlation between NLRP3 inflammasome levels and vitamin D concentrations. Methods: We obtained vitreous samples before vitrectomy from 55 PDR patients, 25 non-diabetic patients with idiopathic macular hole (IMH), and 10 nonproliferative diabetic retinopathy (NPDR) patients. We also collected serum samples from the same patients. Enzyme-linked immunosorbent assay (ELISA) was used to examine NLRP3 Iinflammasome pathway proteins, including NLRP3, caspase-1, IL-1β, and VEGF. In addition, vitamin D concentrations were analyzed in Roche Cobas 6000’s module e601 platform by electrochemiluminescence immune assay. Results: The levels of NLRP3 inflammasome pathway and VEGF increased dramatically in PDR vitreous. H