Abstract: In order to investigate the inhibitory effect of Tricholoma matsutake polysaccharides (TMP) on UVB radiation-induced melanogenesis and the molecular mechanism of melanin synthesis. The study used Tricholoma matsutake as raw material and a new polysaccharide TMP-N was prepared by hot water extraction and DEAE Sepharose Fast Flow purification. The mouse melanoma cells (B16-F10) were utilised as a model to evaluate the effects of TMP-N on melanin content, antioxidant capacity and related gene expression levels after UVB irradiation. The results demonstrated that the molecular weight of TMP-N was 7819.5 Da, mainly composed of glucose, galactose, mannose and fucose. Cellular experimentation demonstrated that the treatment of TMP-N could effectively reduce melanogenesis by inhibiting tyrosinase activity and enhancing the antioxidant capacity of B16-F10 cells. The analysis of the fluorescence quantitative PCR assay demonstrated that TMP-N functioned by downregulating melanogenic pathways through modulation of both PKA and MAPK signalling cascades. This study elucidates the mechanism by which the T. matsutake polysaccharide TMP-N regulates melanin production, providing theoretical support for replacing chemically synthesized photoprotective agents with natural bioactive compounds. The results have significant application value in terms of providing safe and effective protection against UVB radiation damage.