Abstract: The peel strength test is the main method to evaluate the adhesion performance and coating quality of 3-layerpolyethylene (3PE) coating, and the key information concerning coating process control and raw material performance ofpipeline can be obtained by analyzing the peel strength and failure modes of coating peeled. Through the analysis on 40 testresults of 16 typical 3PE samples under different test conditions, 7 types of failure modes of 3PE coating were summarized, and the relationship between various failure modes and the coating process and material performance were analyzed.Futhermore, the effect of test temperature and peeling rate on the failure modes of coating was also studied. The samesample may present different failure modes in different temperature ranges. With the increase of peeling rate, the peelingsection will show increase in roughness and even be torn. Research result provides data support to the judgment on theresults of peel strength test and the improvement of standard indicators of 3PE coating.