The invention discloses a hoistway detecting device which comprises a bracket assembly, a control system and an acquisition system, wherein the control system comprises a control board, a power supply module, a servo motor, steering engines, a first communication module and an illuminating lamp, wherein the servo motor, the steering engines, the first communication module and the illuminating lamp are connected with the control board. The control board is connected with an operation handle through the first communication module. The acquisition system comprises an image camera and a second communication module. The image camera is connected with a mobile terminal through the second communication module. The bracket assembly comprises a supporting frame and a detecting rod. The top of the detecting rod is fixedly connected with the center of the supporting frame. The detecting rod comprises a plurality of successively connected connecting rods. Two adjacent connecting rods are connected through the steering engine. The camera of the image camera is mounted at the end of the detecting rod. The hoistway detecting device with the structure can perform detection on a hoistway and ensures high safety in downwell operation of cable workers.