The flame propagation of an ammonia - hydrogen blended fuel through a porous medium was theoretically and experimentally evaluated in the present study. The laminar flame speed of ammonia - air mixtures is relatively low. The addition of traditional fuels to these mixtures is a feasible method for promoting and maintaining the flame stability of the mixtures. Moreover, the intrinsic characteristics of porous media enhance the heat transfer and heat recovery phenomena, which increases the combustion stability. In this study, a theoretical analysis based on the modified Péclet number and Lewis number was performed to estimate whether an ammonia - hydrogen flame can propagate through a porous medium, and the results of this analysis were verified through experiments.