Abstract: The present disclosure provides a two-stage co-liquefaction mixing-reaction-filtration-heat recovery integrated apparatus, realizing the implementation of a two-stage HTL process; secondly, a nozzle, a receiving chamber, a mixing chamber and a diffusion chamber are disposed at different material feed ports and medium feed ports, and high-speed fluids are fully collided and mixed in these structures; heat of HTL in a first stage is from heat of an HTL product in a second stage, which achieves the recycling of the heat of the HTL product in the second stage, improving economic efficiency; in a first-stage HTL process, through the setting of high-temperature and high-pressure needle valves, so that different first-stage HTL reaction times are selected for different material characteristics; and each first-stage HTL reaction tube is provided with an inclination of 1-3°, and a second-stage HTL generation chamber is provided with a residue scraping device and a salt scraping device.