A correct understanding of the safety status of the sluice base on the soft foundation is very important for a reasonable assessment of the sluice's working behavior,but the hidden dangers of the sluice foundation is located at the lower part of the structure,which is extremely concealed and difficult to detect.Based on the rapidity,elaboration and none-damage of ground penetrating radar(GPR),it has been applied extensively in the field of the structural damage domain.This research takes the damage of bottom board of the soft foundation as an example,with the help of in-doormodel experiment,performs GPR scanning test on the damage of bottom board of the soft foundation,compares those selected technical data and analyze the radar image after data processing.Combind with the engineering practice of the physical model it carres out the test of the hidden damage soft foundation.The result indicate that GPR with on the best parameter settings is reasonable and reliable in detecting hidden dangers in the sluice foundation,and can be used for the diagnosis of hidden dangers in the sluice foundation.