Abstract: Typhoons are among the most destructive meteorological disasters and significantly impact sediment transport and deposition in coastal areas. Sediment magnetic characteristics have been established as effective indicators of sediment sources and changes in depositional environments. However, research on how the magnetic properties of nearshore sediments reflect typhoon activity remains limited. This study collected surface sediments from Sanya Bay before and after typhoon seasons from 2018 to 2021 and conducted systematic rock magnetic and environmental magnetic analyses. The aim was to investigate the spatial and temporal variations in sediment magnetic properties and their potential as indicators of typhoons, potentially offering a new method for identifying paleotyphoons in sediment records. Results indicated that 1. the main magnetic minerals in the surface sediments of Sanya Bay are detrital magnetite and hematite, sourced from rivers and coastal erosion. 2. Based on the magnetic characteristics, Sanya Bay can be divided into three sub-regions: Sanya River estuary, dominated by clayey silt (region Ⅰ); the nearshore area, dominated by sandy silt and silty sand (region Ⅱ); and Xiao Qihe River estuary, dominated by sandy deposits (region Ⅲ). Magnetic minerals content decreases and particle size coarsens from region Ⅰ to region Ⅲ. 3. Magnetic properties of surface sediments in these regions changes significantly before and after typhoons, with distinct patterns. Post-typhoon, hard magnetic minerals decreased and ferromagnetic particles became finer. In region Ⅰ, the composition of magnetic minerals remained largely unchanged, but the content of ferromagnetic minerals increased after typhoons. In regions Ⅱ and Ⅲ, ferromagnetic minerals content decreased, with region Ⅱ showing an increased in relative hard magnetic mineral content and region Ⅲ a decreased. Results suggest that when using magnetic properties to identify typhoon events in sediment records, it is crucial to select appropriate magnetic indicators. Factors like source and type of sediment, depositional processes, and typhoon impact shall be considered.