Abstract: In China, great efforts are devoted to development of pipelines with super-high transmission capacities. However, the quick-opening closure has been the bottleneck of restricting the localization of key pipelines equipment in China. There are many technical challenges on the development and application of the 12.6 MPa/DN1 550 quick-opening closure due to its complex structure, higher pressure, large diameter, low temperature and significant impact loading conditions. Taking natural gas pipelines with the diameter of 1 422 mm and the pressure of 12 MPa in the North Tianshan Mountain in Xinjiang as the example, through stress testing and finite element analysis, two 12.6 MPa/DN1 550 safety self-locking type quick-opening closures have been developed on the basis of structure modification, material optimization, development of cushioning device and overall low-temperature performance test. Reliability of these products has been verified through performance tests and engineering applications. The new equipment provides technical reserves for pipelines with super-high transmission capacities.