Abstract: In this study, a blade-type static mixer model was proposed, and a numerical simulation model was established based on large eddy simulation(LES). The accuracy of LES in gas mixing simulations was verified using a benchmark model. The blending process of hydrogen and methane was analyzed, and the mixing performance and mechanism of the static mixer were explored in terms of key parameters. Results show that compared with the direct mixing method, the blade-type static mixer significantly improves the mixing homogeneity of hydrogen in natural gas pipelines. The flow velocity is positively correlated with pressure loss, and the impact of the hydrogen injection pipe diameter is relatively small. Local vortices generated at the blade edges can effectively enhance the contact area between hydrogen and methane, facilitating the mass transfer process between the two gases. The above findings provide theoretical value and practical significance for the development and application of key equipment for hydrogen blending in natural gas pipelines.