Taken three typical semi-submersible floating foundations, OC4, Windfloat and Ideol, as the research objects, based on the main characteristics of the three typical floating foundations, the hydrodynamic model is established by AQWA software. Based on the three-dimensional potential flow theory, the comparative analysis of the hydrodynamic performance, the time domain motion response under combined actions of wind, wave and current in the South China Sea and the adaptability at different water depths is carried out. It is concluded that: the surge performance of three kinds of foundations is similar; OC4 foundation has the smallest mean and peak values of heave response in time domain and is of better comprehensive performance; the pitching Response Amplitude Operator (RAO) of Windfloat foundation is the smallest, the mean and peak values of the heave response in the time domain are the largest which means it is of poorer heave performance; compared with OC4 and Windfloat, the heave RAO of the damping pool foundation in low frequency is smaller, the pitch RAO is much larger, the mean value of the pitch response in the time domain is the smallest and the peak value is the largest, which shows the instability; the RAO of OC4 foundation and Windfloat foundation in shallow water is obviously enlarged, OC4 foundation is of good adaptability in deep water, Windfloat foundation is of good adaptability in medium-depth water, the heave and pitch RAO of the damping pool foundation varies not obviously with the increase of water depth which shows it is of a better adaptability in shallow water. The analysis results can provide reference for the selection and design of floating foundation in the South China Sea.