Due to various reasons, the inherent quality for Weihe River dike remains poor. There are many hidden defects in dikes, such as cracks, holes etc. so that the actual flood protection ability of dikes is low. And it is difficult to resist the impact of the design flood. In order to ascertain the number, distribution and depth of these hidden defects, etc., electrical detecting technique was applied and studied for detection of hidden defects. At the same time, in order to verify the correctness of the detection results of hidden defects, the engineering geological survey for the purpose of verification was carried out on the detection dike sections. Survey results confirmed the reliability of detection conclusions.