The grouting quality of the grouting sleeve connector is crucial for ensuring the stability of prefabricated building components. In practical engineering, the grouting sleeve is often arranged with multiple sleeves, and there is no feasible nondestructive testing method for testing the complex arrangement of the sleeve grouting joints in the embedded state. Building upon the feasibility of nondestructive detection of single socket grouting connectors, this study discusses the feasibility of defect detection and the severity of defects. Simulation results are used to investigate the choice of the best excitation signal. For different simulated damage cases, it is proven that the selected damage index can be very sensitive, and both the location and the extent of the damage can be detected successfully. The results demonstrate that with the section injury rate ranging from 10% to 40%, the reverse focus peak decreased from 20% to 60% compared to no injury. The effectiveness of the Lamb−wave−based time reversal method in detecting the internal grouting defects of multiple grouting sleeve joints is proven. This paper focuses on the detection study of the Lamb−wave−based time reversal method and proves its ability to perform the detection task effectively and accurately.