Abstract: With entering into new active period of the earth, earthquakes take place more frequently. According to recent researches, earthquake disasters in urban areas are mainly caused by the underlying active faults. Active faults are those moved since Late Quaternary. Since 1990s, new methods for active fault detecting have been explored. This paper analyzes the properties of active faults and summarizes the detecting methods for active faults on the basis of previous practices and the authors' experiences. The methods of active fault detecting can be generally classified into three aspects, i.e., geophysical methods, geochemical methods and borehole drilling methods. The three methods all have their own advantages and disadvantages. If engineers combine the three methods in active fault detecting, they will achieve their work much more accurately and effectively.