Abstract: Through test and research on fracture toughness of X52 thin wall pipe product, including sample making, test principle and test procedure, get the J integration of X52 thin wall pipe*s mother material and weld material, thus provide a theoretical base for further researching and analyzing the problem of pressure bearing and safety of the pipe product in oil pipeline engineering. And points out simultaneously it is convenient, reasonable and economic for the pipe product to be tested for its fracture toughness of J integration with small samples.