With the establishment of the National Petroleum and Natural Gas Pipeline Network Group Co., Ltd in December 2019, a significant shift has been observed in recent years toward the integration of long-distance and urban gas pipelines into a singular “one natural gas pipeline network.” This integration presents complex technical challenges, particularly in managing the mix of multiple gas sources. The deployment of diverse supply sources, optimization of end-user gas usage management, and the selection of strategies for complex scenarios—such as the unpredictable peak shaving demands of power plants, new end-of-network gas users demands, and ensuring the safe and stable operation of the integrated network—have become pressing issues. This study focuses on the Pearl River Deltas urban agglomeration and its integrated natural gas pipeline network. It employs the Wobbe index criterion to evaluate the interchangeability of four different gas sources within the network. Utilizing TGNET software, both steady state and dynamic hydraulic calculations and simulations are performed. Through simulation analysis, a comprehensive evaluation is conducted, taking into account factors such as the calorific value of the gas, gas flow, operating pressure, and incident scenarios, as well as the safety impacts. The study proposes an optimal gas source allocation strategy and modification and expansion recommendations tailored to the needs of the integrated natural gas pipeline network. These proposals are aimed at guiding the networks operation and future development; and serve as a reference for the efficient and safe management of integrated multi-source natural gas pipeline networks.