Abstract: The application situation of detective techniques for hidden troubles of dams and dikes in China is systematically expounded. Three key problems about uncertainty of detective results in practical applications are summarized and analyzed;the first is the variety of medium materials and uncertainty of its characteristics which will impact the detective results seriously;the second is the contradictions between the scale of hidden troubles in detective objectives and apparatus resolution powers;the third is the uncertainty and difficulties in interpretation of detective results. Finally, some countermeasures and recommendations are presented so as to strengthen experimental studies on the detective impact caused by different mediums, to apply various detective techniques to the same project in order to compare the results, and to train technicians with multi-subject knowledge in order to enhance their comprehensive diathesis.