With the rapid growth of onshore wind power installations, higher demands are placed on the reliability, efficiency, and cost-effectiveness of wind turbine foundations. This study examines the mechanical characteristics of prefabricated dense ribs foundation for onshore wind turbines under complex load conditions. Firstly, the structural characteristics of prefabricated foundations used in onshore wind turbines were thoroughly studied, leading to the proposal of a new prefabricated dense ribbed foundation (PDRF). Secondly, a 1:6 scaled model experiment of PDRF was designed according to the model similarity criterion, and the mechanical characteristics of PDRF subjected to extreme load were investigated by using the vertical, horizontal, and moment (V-H-M) complex loading method. Finally, the V-H-M complex loading method experiments provide data on foundation stress, displacement, and tilt, which are analyzed for the scaled model. The research results indicate that under normal operating loads, the stress, inclination rate, and stability of the foundation meet the requirements. At this point, adjacent foundation blocks will not move incorrectly and will remain in a coordinated motion state. Through analysis of the foundation structure revealed that the concrete at the junction of the pillar and ribbed beam experienced compressive failure when the PDRF was subjected to 1.44 times the extreme load. At the same time, the rapid movements of adjacent foundations were not coordinated, resulting in significant misalignment. © 2025