Abstract: Two-phase flow cooling technology has become a critical solution for addressing the challenges of high integration and high heat flux in electronic devices and microwave components. The flow resistance characteristics of phase-change working fluids directly influence the thermodynamic features of cooling systems. Taking the large-scale phase-change cooling pipe network as the research object, a pump-driven two-phase flow test platform and thermal simulation system are established. Under conditions of variable heat consumption and variable flow rate, experiments are conducted to investigate the gas-liquid flow resistance characteristics of the two-phase flow system. Specifically, experiments are performed to measure the flow resistance curve of two-phase working fluids in typical piping configurations. The results indicate that in two-phase flow cooling systems, the piping resistance tends to exhibit linear relationships with both flow rate and heat consumption. Notably, in elbow abrupt change regions, an increase in system heat consumption significantly enhances the slope of the linear relationships between flow rate and resistance, which suggests that in phase-change flow, the vapor phase plays a critical role in influencing the piping resistance of the system. This study summarizes the gas-liquid flow resistance characteristics within the piping of two-phase flow cooling systems, which provides an important theoretical basis and reference for the application of phase-change cooling technology in engineering design and practical implementations.