Embankment slope failures have recently occurred frequently due to the natural disasters. The typical regulation for embankment constructions is the degree of compaction on the top of the embankment. There is no regulation for degree of compaction on the embankment slope. In this study, in order to develop a new system for evaluating the degree of compaction on the embankment slope, non-destructive testing method which measures ground stiffness was developed and performed in laboratory and in-situ. In this paper, firstly, in order to investigate the correlation between the degree of compaction and ground stiffness obtained by the non-destructive testing method, the non-destructive tests were performed on specimens compacted with various moisture contents and degrees of compaction in laboratory. Secondly, the non-destructive tests were performed on the embankment slope and the degree of compaction of embankment slope was estimated by using regression equations in laboratory. Finally, the validity of the estimated degree of compaction on the embankment slope by non-destructive method was confirmed by comparing to the results of RI method.