Abstract: Internal solitary waves (ISWs) are important dynamic phenomena in the northern South China Sea, characterized by abrupt occurrence, large amplitudes, and strong current velocities, posing serious threats to offshore engineering safety. In recent years, substantial progress has been made in oil and gas exploration over the deep-water continental slope region. However, observational studies focusing on the statistical characteristics of ISWs in this region remain relatively limited. Based on continuous full-depth mooring observations from July 28, 2021 to August 16, 2022, the key parameters, occurrence patterns, and influencing mechanisms of ISWs are systematically investigated. The results indicate that ISWs propagate northwestward, with amplitudes predominantly ranging between 40-120 m and a maximum amplitude of 186 m. Moreover, 84.1% of the observed ISWs exhibit peak westward velocities exceeding 1.0 m/s, and 89.9% exhibit peak northward velocities exceeding 0.4 m/s. In terms of temporal variability, on the diurnal timescale, ISWs show concentrated occurrences during 05:00-08:00 and 17:00-20:00. On the lunar monthly timescale, ISWs occur more frequently and demonstrate greater intensity during spring tides. Notably, ISW intensity is highly sensitive to variations in the background thermocline depth. During the passage of cyclonic eddies, ISWs become stronger due to the uplifted thermocline, thereby increasing the potential for the development of extreme ISW events. This study elucidates statistical characteristics of ISWs over the continental slope region and their performances under multiscale background processes, providing guidance for selecting operational windows and designing structural protection measures for offshore engineering activities. It is recommended that high-risk offshore operations be avoided during periods when cyclonic eddies and spring tides coincide.