The invention discloses a multi-section tubular type sludge rapid thermal hydrolysis treatment process. The method includes the steps of sending sludge into a crude sludge pump to be primarily mixed with and preheated by flashing steam, pumping the preheated object into a first-stage dynamic mixer to be secondarily mixed with and preheated by raw material steam, making the secondarily mixed and preheated sludge automatically flow into a second-stage static mixer under excess pressure to be finally mixed with and heated by mixed steam coming from a steam ejector, making the tertiarily mixed and heated sludge automatically flow into a rapid-assembled tubular type hydrothermal reactor under excess pressure for reaction, making the sludge meeting the reaction requirements enter a flash tank to be flashed, and further conducting dehydrating or direct anaerobic digestion on the flashed sludge. By means of the process, through a large amount of latent heat generated by directly mixing steam and sludge, the sludge is heated till cells are broken and cytosol is dissolved out, and therefore the dehydrating performance and anaerobic digestion performance of the sludge are changed. The high-grade steam is subjected to flashing heat transferring, so the utilization efficiency of the steam is the highest.