Abstract: Waves are one of the primary external forces causing soil erosion in the riparian zone of the Three Gorges Reservoir. Studying the characteristics of nearshore wave forces is crucial for understanding soil erosion processes in this area. However, the spatial and temporal variations of nearshore wave forces in the Three Gorges Reservoir remain unclear. This paper employed in-situ observation methods and relevant recommended formulas to quantitatively calculate and analyze the spatiotemporal variations of nearshore wave forces in the Three Gorges Reservoir, main and tributary streams. The results indicated that: (1) Nearshore wave forces in the Three Gorges Reservoir exhibited significant spatial and temporal heterogeneity (P<0.01), with values ranging from 0.02 to 12.14 kPa, showing a reservoir impounding cycle. The frequency distribution of nearshore wave forces could be fitted using the Lorentz distribution curve. (2) Nearshore wave forces increased with rising water levels. At a water level of 175 m, the average nearshore wave force was 1.7 times and 1.2 times that at 150 m and 165 m water levels, respectively. At 150 m water level, nearshore wave forces primarily ranged from 0 to 1.5 kPa, with a cumulative frequency of 91.4%. (3) There were significant differences (P<0.01) in nearshore wave forces between the main and tributary streams. The average nearshore wave force in the mainstream was three times that of the tributaries. (4) The variation in nearshore wave forces across different reservoir sections was irregular. However, at the same water level, the average nearshore wave forces in the Zigu, Badong mainstreams, which were closer to the Three Gorges Dam, were significantly higher than those in the Zhongxian mainstream, that was farther away from the dam. (5) The peak values of nearshore wave forces during typical days coincided with shipping activities, indicating that the intensity of shipping activities was a key factor causing significant differences in nearshore wave forces between the main and tributary streams. These research findings provided scientific references for studying the hydrodynamic characteristics of nearshore areas and the soil erosion environment in the riparian zone of the Three Gorges Reservoir.