In this study, non-destructive methods were applied to detect cavities behind face-slab of concrete-faced rockfill dam (CFRD). This study reviewed the effectiveness of the field IE, MASW, MIRA shear wave tomography and GPR findings. IR techniques also reviewed as an additional method of exploration to reinforce the proposed methods of exploration. Among previous methods, IE exploration was concluded most appropriate as an efficient way to detect cavity of the CFRD. Nevertheless, additional reinforcement investigation is required because the result of a single exploration is difficult to reduce the uncertainty.