Fracture toughness index of steel pipes is often required to be optimized during pipe production, in order to reduce the failure risk of large-diameter thick-walled pipes for the economic efficiency. For this purpose, an experimental study was carried out on the DWTT (Drop-Weight Tear Test) of thick-walled steel pipes. Twice low-temperature full-scale burst tests were conducted on OD1422 × 38.5 mm X80 steel pipes under an environment of – 5 ℃, which verified the low-temperature crack arrest ability of the steel pipes. A systematic investigation was made to obtain the crack propagation speed and the fracture morphology characteristics of the steel pipes. The test results showed that the SA (Shear Area) values of the full-wall-thickness DWTT specimens of the tested pipes were 71% and 75%, respectively. And the crack propagation speed of the pipeline reached a maximum of 102 m/s, then attenuated rapidly and achieved crack arrest. The analysis suggested that affected by the deformation on the hammered side, the full-wall-thickness specimens underestimated the true toughness of the steel pipes, resulting in conservative DWTT test results. The fracture morphology of the burst test was more consistent with that of the thinned DWTT specimens. The thinned DWTT specimens can more accurately characterize the true toughness of the steel pipes. When the average SA value of the full-wall-thickness DWTT was not less than 71%, the steel pipe had sufficient toughness to achieve self-arrest under a pressure of 12 MPa. The findings can provide the key technical basis for the formulation of DWTT indexes for the thick-walled steel pipes in pipeline engineering.