Abstract: Synergi Gas simulation software is used to construct the regional pipeline network transportation process model composed of four in-service natural gas pipelines of A, B, C and D in a certain region, and to simulate the influence of different hydrogen blending ratios and injection points on the overall transportation capacity of the pipeline network. The simulation results show that under the premise of the distribution pressure of 4.0 MPa, the distribution capacity of the downstream line D becomes the key to restrict the overall hydrogen transport capacity of the pipeline network. When line A in the upstream is taken as the hydrogen blending point, the maximum hydrogen doping ratio is 20%, while when line C in the midstream is taken as the hydrogen blending point, the maximum hydrogen blending ratio can be increased to 50%. Therefore, it is suggested that the access point close to the end user can be selected in practical operation to improve the proportion of hydrogen blending delivery. After increasing the proportion of hydrogen incorporation, in order to ensure that the total calorie-value of end users remains unchanged, it is necessary to consider the transport coefficient relative to the proportion of hydrogen incorporation to make up for the calorie-value gap caused by hydrogen.