Abstract: Objective: To explore the effect of dexamethasone (Dex) sodium phosphate nanomaterials (Nano-Dex) on interleukin (IL) -1β-induced inflammation in primary rat chondrocytes. Methods: Transmission electron microscopy was used to observe the morphology of Nano-Dex nanoparticles; Malvern particle size meter was used to detect the particle size as well as the potential of Nano-Dex. SD rat chondrocytes were cultured, and the cells were randomly divided into blank group, IL-1β group, IL-1β+Dex group, and IL-1β+Nano-Dex group. The expression levels of matrix metalloproteinase (MMP) 13, MMP3, IL-1β, IL-6, collagen type II alpha 1 (Col2a1) and proteoglycan (ACAN) genes in chondrocytes were detected by reverse transcription-quantitative PCR (RT-qPCR). The expression of MMP13 was observed by immunofluorescence staining. The expression levels of MMP13, Col2a1, IL-6, IL-1β, P65 and Caspase 3 in chondrocytes were detected by western blotting. Results: Nano-Dex had a rounded shape, uniform size, diameter of about 90 nm, and a positive charge. Compared with the blank group, the expression of cartilage repair genes Col2a1 and ACAN in the IL-1β group was down-regulated, while the expression of inflammatory genes IL-1β, IL-6, MMP3 and MMP13 was up-regulated (all P< 0.05). Compared with the IL-1β group, the expression of Col2a1 gene and protein as well as the expression of ACAN gene in the Nano-Dex+IL-1β group were up-regulated, and the expression of IL-1β, IL-6, MMP3 and MMP13 genes as well as the expression of MMP13, P65, IL-6, IL-1β and Caspase 3 proteins were down-regulated (all P< 0.05). Immunofluorescence results showed that the fluorescence intensity of MMP13 in the IL-1β+Nano-Dex group was significantly lower than that in the IL-1β group (P< 0.05). Conclusion: Nano-Dex can effectively inhibit IL-1β-induced chondrocyte inflammation.