The invention belongs to the field of engineering machinery integrated information equipment, and particularly relates to an engineering machinery multi-arm anti-collision mechanism, a multi-arm heading machine and an anti-collision method of a multi-arm heading machine. The anti-collision mechanism comprises an active anti-collision mechanism, a passive anti-collision mechanism, a controller andan alarm module, and the active anti-collision mechanism, the passive anti-collision mechanism and the alarm module are connected with the controller, wherein the active anti-collision mechanism is used for locating position information of adjacent mechanical arms during operation, and the controller controls the mechanical arms to stop action according to a preset safe distance; the passive anti-collision mechanism is used for controlling emergency stop action of the mechanical arms and engineering machinery by cutting off electricity and an oil pump circuit by the controller when the activeanti-collision mechanism fails in the case that the adjacent mechanical arms exceed the preset safe distance; and the alarm module is used for alarming and reminding of the safe distance of the mechanical arms according to trigger signals of the controller. According to the engineering machinery multi-arm anti-collision mechanism, the multi-arm heading machine and the anti-collision method the multi-arm heading machine, the failure rate of cutting arms during tunneling is effectively lowered, high engineering application prospects are achieved.