A method for sintering a self-heat-insulation brick by using sludge and dug subway earth comprises steps as follows: the sludge is dewatered by a filter press until the water content reaches 40%-70%; the dug subway earth is naturally aired for 1-2 days until the water content is 20%-30%; 20-30 parts by weight of the sludge and 70-80 parts by weight of the dug subway earth are mixed, stirred, pre-homogenized for 6-12 h and aged for 12-24 h; 0.01-0.1 parts by weight of a sawdust pore-forming agent or a straw pore-forming agent are added and mixed uniformly, and a blank is obtained; the blank is subjected to vacuum plastic extrusion molding, and a brick body is obtained; the brick body is dried until the water content is 5%-8%, the brick body is sent into a tunnel kiln to be roasted at the sintering temperature of 950-1,050 DEG C for 5-8 h, and the self-heat-insulation brick is obtained. The sludge and the dug subway earth are used for sintering the brick, internal combustion coal powder is not required to be added, waste is turned into valuable, and environment pollution is reduced; the process is simple, the cost is low, the strength is high, and the appearance is good.