The invention discloses a semi-automatic sector cutting platform comprising a sector platform body, a rotation center support, a cantilever, an automatic trolley, a traveling track, a cutting torch mounting rack and a cutting torch. The sector platform body and the rotation center support are both mounted on the ground, and the rotation center support is located at the circle center corresponding to the sector platform body. The cantilever is disposed above the sector platform body and consists of a front cantilever section and a rear cantilever section hinged to each other, one end of the front cantilever section is fixedly connected with the automatic trolley, and one end of the rear cantilever section is connected with the rotation center support horizontally and rotatably. The traveling track is fixedly connected on the front cantilever section, and the automatic trolley is disposed on the traveling track and moves along the same. The cutting torque mounting rack is mounted on the front cantilever section in a fixing position adjustable manner, and the cutting torch is detachably mounted on the cutting torque mounting rack. The semi-automatic sector cutting platform has the advantages of improvement in cutting accuracy, simplicity in production, low cost, flexibility in operation, high practicality and low requirement on mounting sites.