Abstract: Pipe piles need to be connected in actual projects for the design length constraints of a single pile. Nowadays, the main pile extension method is welding. The quality of welding joints will directly affect the bearing capacity and stability of pile foundation. During the construction process of pipe pile, the non-standard piling operation, changes of soil layers and other factors may make joints become loose or broken and lose the overall stability of pipe pile, leading to serious security problems in the end. In order to study low-strain integrity test effect on the detection of the pipe pile joints and correctly identify the quality of joints, a joint model is established according to the connection feature s of pipes pile Numerical simulation is carried out. Some conclusions are drawn by making model piles, conducting field tests and analyzing theoretical and test curves.