The invention discloses a crane collision avoidance detection and control system. The crane collision avoidance detection and control system is used for detecting the process that a manually controlled bridge crane which is installed in the air and a gantry crane which is located on the ground and runs automatically without manual operation are used in cooperation for work, the bridge crane on the upper layer is a crane which is controlled manually, and the operation of the bridge crane is controlled by a dispatcher on the ground through random transfer. According to the crane collision avoidance detection and control system, a laser scanner, a trolley safety limit switch and more than one PLC control unit act on one another, wherein the laser scanner is used for scanning the outline of an object in the operation area and programming to set the warning speed reduction and collision avoidance alarm outline of the scanned object, the lifting of the crane on the upper layer and trolley safety signals are linked to achieve the active detection and active collision avoidance control of the crane on the upper layer, the passive collision avoidance or operation stop control of the crane on the lower layer in the process of independent and automatic operation, and the collision avoidance control of emergency intervention of central control room integrated monitoring, and therefore, safety is higher, and the control method meets the process requirements on site better.