In order to improve the efficiency of pipeline transportation, a 0.8 design factor is used for gas pipelines in Level 1 area of the western section of West-to-East China Gas Pipeline III for the first time. In accordance with the design requirements, the hoop stress generated in the pipeline strength pressure test should be no less than 100% of the specified minimum yield strength (SMYS). For such a high pressure test strength, there is no domestic experience to follow. This paper studies the approach using P-V curve for pressure test control combined with the actual pressure test of pipelines with a 0.8 design factor and then validates the feasibility and accuracy of such kind of approach through the hydrostatic test of the test pipe section with a 0.8 design factor in the West-to-East China gas pipeline III. Practice has proved that the hydrostatic test of gas pipelines with a 0.8 design factor in Level 1 area is successful and the use of P-V curve method for pressure test control is feasible. This great success accumulates a wealth of experience for the application of pipelines with a 0.8 design factor in Level 1 area, laying a good practice foundation for the promotion of 0.8 design factor in Level 1 area of China.