The paper introduces the characteristics of cross-hole wave velocity testing and sedimentary strata and cross-hole wave velocity testing is applied to the sedimentary strata. For there are several strata inter-beded with soft stratum in the sedimentary strata area, reasonable parameters, drilling, deviation measuring, the space of boreholes and locations of testing points are designed to conduct the wave velocity test. The result shows that the cross-hole wave velocity testing can be applied to the inter-beded stratum and thin stratum of sedimentary strata and obtain reliable result.