Abstract: We set up finite element model of anchorage system to study anchorage quality detection of anchorage system by stress wave method and studied propagation properties of stress wave in the case of the increasement of defect length of anchorage system. We calculated multiscale entropy (MSE) of reflected signals and found that the MSE of reflected signals obtained from defective anchorage system are larger than the defectless one on most time scales, that means the complexity of reflected signals obtained from defective anchorage system is higher. A parameter named pseudo R square (PR²) was defined to describe the deviation degree of two MSE curves of the reflected signals obtained from defective and defectless anchorage system quantitatively. By computing, we found that the longer the axial length of defect is, the smaller the value of PR² is; the larger the deviation degree of the two MSE curves is, and the higher the complexity of reflected signals obtained from defective anchorage system is. This shows that the anchorage quality can be evaluated effectively by MSE method.