The technology of hot composite foam displacement refers to the injection of high-temperature flue gas and foaming and stabilizing agent into wells with a certain concentration, and after meeting the formation water, a composite foam system is formed in the reservoir. This foam displacement technology involves thermal function and so is related to nitrogen, carbon dioxide and foam flooding characteristics. After analyzing seepage flow law of hot composite foam system, seepage flow experiment of composite foam under high pressure was conducted, and seepage flow ability of hot composite foam in porous media was investigated. In the experiment, surfactant HY-3 was chosen as the foaming agent and hot flue gas was chosen as the foaming gas, and high-pressure hot foaming apparatus was employed in experiments. The experimental results indicate that the surfactant HY-3 could form stable foam in porous media, and the foam has strong ability of plugging. It is concluded that the sealing performance of foam is improved with increasing permeability and resistance coefficient and with incresing injection rate and foam strength. After foam injection, sealing characteristics of heterogeneous cores is better than that of homogeneous cores. The foam pressure has a process of transmission in porous media. In this process, with the increase of injection volume, pressure from the inlet to the outlet increases gradually, which indicates that stable foam has been formed inside the core.