The invention discloses a door-frame-type arching mounting trolley. The door-frame-type arching mounting trolley comprises a 20-ton crawler, a first lifting assembly, a second lifting assembly, an upper transverse longitudinal beam assembly, a main frame lifting oil cylinder, a main frame lifting oil cylinder seat assembly, a bottom longitudinal beam assembly and a platform assembly. The 20-ton crawler is mounted at the lower end of the first lifting assembly and rotatably connected with the first lifting assembly through a crawler steering assembly; the first lifting assembly is mounted on the second lifting assembly; the main frame lifting oil cylinder is mounted on the upper portion of the second lifting assembly; the main frame lifting oil cylinder seat assembly is mounted on the upperportion of the main frame lifting oil cylinder; a main frame oil cylinder lifting assembly is fixed to the lower portion of the bottom longitudinal beam assembly; and the upper portion of the bottomlongitudinal beam assembly is provided with a front-end door frame vertical column assembly and a middle and rear end door frame vertical column assembly. The door-frame-type arching mounting trolleyis simple in structure and convenient to assemble and disassemble, and the problems that the excavation speed is low, and safety performance is low are solved.