Abstract: To deeply study the use of transient Rayleigh wave method for detecting the grouting effect of karst roadbed, 12 sections in the field test area are selected, and 1470 test sample points are collected. The comparative tests on 4 important test areas before and after grouting and long-time trace tests are carried out. The confirmative tests on other 8 test areas are performed. Combined with the multiple confirmative methods of field water pressure tests and borehole coring and based on the effective test data, the criteria for detecting grouting effect of three different subsurface media such as cave, rock mass and soil are proposed by means of the transient Rayleigh wave method, and the suitable detecting time is 7 days after grouting. The confirmative tests show that the results are credible.