Deep foundation pit excavating device and operation method

The invention discloses a deep foundation pit excavating device. The deep foundation pit excavating device comprises a base layer and a machine head, a base plate is arranged on the surface of the base layer, a traction frame is arranged on the surface of the base plate, a brake assembly is arranged on the outer wall of the traction frame, a diagonal draw bar is arranged between the outer wall ofthe traction frame and the base plate, an anti-falling assembly is arranged on the inner wall of the traction frame, a spiral column is connected into a top plate of the traction frame in an insertedmode, an extending combined rod is arranged at the upper end of the spiral column; and the invention further discloses an operation method of the deep foundation pit excavation device, and the operation method comprises the following steps of base layer treatment, frame body installation, foundation pit excavation, traction piece lengthening and machine head lifting. The deep foundation pit excavating device has the benefi