The standard "ISO/TS 16774-4-2016 Test methods for water leakage cracking repair materials for underground concrete structures, Part 4: Test methods for adhesion to wet concrete surfaces" specifies experimental methods for testing the adhesion of water leakage cracking repair materials for underground concrete structures on wet concrete surfaces. This method is mainly used to evaluate the bond strength of repair materials to concrete surfaces in a wet environment, ensuring that the repair materials can be effectively attached and work for a long time under actual use conditions. During the test, the repair material needs to be coated on the wet concrete surface and the adhesion of the repair layer to the concrete is measured through specific tensile or disbonding tests. This standard provides a reliable test basis for the performance evaluation of restoration materials and helps to ensure the long-term safety and stability of underground concrete structures.