Abstract: Natural gas pipeline network, demanding gigantic investment and operating costs, is one of the most important infrastructures in the petroleum industry. It is significative to do the optimization research on this system. Based on the analysis of the problem, this paper introduces the domestic and overseas approaches from 1980s, analyzes the shortages of the classical approaches. These multi-layer hierarchical optimizations couldn't reflect the nature of the system as a whole, so the solutions are not global optimum. How to build logical models, which can cover layout, design and run etc, will be a research direction in the future. Alternately, the new intelligence optimization should be applied in the problem. In order to generalize the optimizing algorithmic procedures of the natural gas pipeline network, many methods, having complementary advantages, should be integrated organically.