Abstract: Active fault detection is of great practical significance for the whole regional planning, seismic earthquake fortification and mitigation of damage to various facilities when an earthquake occurs. South China has developed economy and complex seismicity. The development characteristics of active faults are quite different from those of North China and Northwest China. The Quaternary overburden is thin, and the underlying bedrock is mostly granite with well-developed water network. It is difficult to obtain good data by using conventional geophysical methods to detect seismically active faults. Based on the research of active fault detection in Shenzhen, the method of high resolution shear wave in land area and high frequency longitudinal wave in water area was combined to detect active faults. The detection results are in good agreement with drilling data and can be used as an important method in active fault detection and engineering geology in South China.