Nonlinear internal waves (NLIWs) are prevalent on the northern continental shelf south of Hainan Island in the South China Sea. However, our understanding of these NLIWs is still in a preliminary state. In the study, through a synergistic analysis of satellite observations, in situ measurements and numerical simulations, we take a step toward fully elucidating the generation and propagation process of the NLIWs on the northern continental shelf south of Hainan Island. Both mooring and satellite observations suggest that the Xisha Islands remotely generate the NLIWs on the northern continental shelf south of Hainan Island; moreover, more than one source exists in the Xisha Islands. Based on the realistic topography, stratification and tidal forcing, two-dimensional numerical simulations using the MITgcm reveal that the NLIWs observed on the continental shelf can be generated from different sills in Xisha Islands through the internal tidal beam or mixed tidal lee wave regime. Furthermore, the internal tide energy flux estimation suggests that the locally generated internal tides emanating from the continental shelf break play an essential role in the baroclinic energy field of the deep sea while their influence on the baroclinic energy field of the mid-continental shelf can be almost negligible.