Abstract: Hydrogen-doped natural gas pipeline transportation is an effective means to solve the regional mismatch of hydrogen energy resources in China and realize the large-scale transportation of hydrogen energy. The compressibility factor and throttling effect coefficient of hydrogen-doped natural gas are different from those of natural gas, among which the compressibility factor is a key parameter for hydraulic calculation of long-distance hydrogen-doped natural gas pipeline, and also one of the key parameters affecting the accuracy of hydrogen-doped natural gas metering. At present, there are scarce international studies on the compressibility factor of medium and high proportion of hydrogen-doped natural gas, and scarce experimental test data on the compressibility factor of hydrogen-doped natural gas. This paper carries out the experimental test of compressibility factor of methane-hydrogen-nitrogen (CH₄-H₂-N₂) ternary gas mixture under pipeline working conditions, analyzes the change rule of compressibility factor with hydrogen doping ratio, pressure and temperature within the experimental working conditions, and evaluates the adaptability of four equations of state, namely, BWRS-EOS, PR-EOS, AGA8-92DC-EOS, and GERG2008-EOS, for the calculation of compressibility factor of hydrogen-doped natural gas. In order to facilitate the engineering application, a fast calculation model of the compressibility factor of hydrogen-doped natural gas is proposed.