Monitoring device for monitoring position of hoisted material on crown block

The utility model relates to the technical field of cranes, in particular to a monitoring device for monitoring the position of a material hoisted on a crown block, which is in signal connection with a crown block operating system and comprises a crown block, a rotary scanner and a range finder, the crown block comprises a cart and a trolley arranged on the cart; a range finder for monitoring the real-time position of the trolley is arranged on the trolley; the trolley is provided with a lifting device for grabbing and hoisting materials and an absolute value encoder for confirming the height of the materials hoisted on the lifting device. The rotary scanner is connected to the cart and is in signal connection with the distance measuring instrument and the absolute value encoder so as to accurately shoot the position of the material; and the crown block operating system receives and displays a picture shot by the rotary scanner. The range finder and the absolute value encoder are arranged so that the position