As a key link between carbon source and carbon sink in carbon capture, utilization and storage(CCUS) technology, CO₂ pipeline transportation will play an important role in the process of carbon neutralization in the future. For the pipeline water hammer condition, the pressure oscillation may exceed the pressure in the pipe and be lower than the inlet pressure of the pump. At present, the water hammer and control theory of supercritical CO₂ pipeline is not mature. A mathematical model based on the law of conservation of mass, momentum and energy was established to describe the one-dimensional gas flow in the pipeline. The characteristic line method was used to solve the model, and the MATLAB programming was used to calculate. The simulation results were compared with the simulation results of the gas transmission system model proposed by Kiuchi and the simulation results of the commercial software OLGA. The results show that the simulation results are generally consistent with the simulation results of the gas transmission system model. Compared with OLGA software, the maximum relative errors of pressure and flow are 0.02% and 2.32%, respectively, which meet the requirements of engineering calculation accuracy. For the fast transient process of pipeline parameter change caused by pipeline compressor start and stop, valve emergency switch and rapid change of flow in a short time, the rapid change value is set to simulate. The established model can calculate the parameter change of each node with high accuracy, which can provide theoretical support and technical support for the localization of supercritical CO₂ pipeline transportation process simulation software.