Abstract: In the case of strata exploration by means of sonic device,it is not strange that disturbance noises are mixed with useful sonic signals that negatively influences the accuracy of exploration results.The separation of disturbance noises from useful sonic signals is always very difficult,however absolutely necessary.The principle of the nwe Optimum Frequency Matching Method(OFMM) and the computational logic for searching optimum frequency of sonic signals by using OFMM are described.The practice shows that reasonable separation of disturbance noises from useful sonice signals and obtaining of various useful sonic signals under condition of heavy noise disturbance can be realized as OFMM is adopted.