The invention provides a large-displacement drawing machine for a constant-resistance anchor tie and a usage method thereof. The large-displacement drawing machine comprises a supporting column, a hoop, a rotating seat, a hollow hydraulic cylinder and a hydraulic pump, wherein the supporting column can be supported in a tunnel; the hoop is sleeved on the supporting column; the rotating seat is assembled on the hoop; the hollow hydraulic cylinder can draw the anchor tie; the hydraulic pump drives the hollow hydraulic cylinder; the length of the supporting column can be adjusted; two ends of the supporting column can be leaned against on the bottom surface and the top surface of the tunnel, which are opposite; the hoop can be detachably mounted at different positions on the supporting column; the rotating seat can be fixedly arranged on the hoop at different rotation angles; the hollow hydraulic cylinder is connected with the hydraulic pump; and the hollow hydraulic cylinder is assembled on the rotating seat. The large-displacement drawing machine for the constant-resistance anchor tie has the advantages of large displacement range, high bearing capacity, simple structure, convenience in movement, flexibility in operation, and safety and reliability in transportation.