This anti-collision device is a tower crane safety system. It has the following functions: CXT/800 system protection Tower crane Anti-collision protection If tower cranes are with the same height, this system can control and handle it effectively, once detecting that the running jibs interfere with each other automatically. While not with the same height, this system can also work effectively once acticipating the hook or cable of the higher tower crane may collide the jib or couter jib of lower one. Zone(obstacle) anti-collision Due to the complexity of some sites,the system can automatically and effectively determine up to 10 prohibited zones in which the hook or jib are not allowed to operate. Boundary protection Complicated environment usually exists around work CXT/800 system can be preset with a up to 30-point boundary protection area in which the operating or over-flying of hook is not allowed. It can effectively prevent accielents from happening. Pre-alarm/alarm and control CXT/800 system allows the operator to work at maximum efficient way and optimize the use of crane. once monitoring the pre-set data for possible collisions in crane interference area and over-flying of sensitise areas, there will be pre-alarm and visual and audible alarm and the system will stop the maneuver automatically to maintain a safety margin.