The invention discloses a hydraulic negative flow control loop and method, an executing mechanism and a system. The control loop comprises an unloading loop, a first negative flow control loop and a second negative flow control loop. The unloading loop is connected to a hydraulic oil tank and an oil outlet of a corresponding variable pump in parallel, and used for enabling hydraulic oil output by the variable pump to reach the hydraulic oil tank through the unloading loop under the situation that a hydraulic system action signal is not received. The first negative flow control loop is connected to a corresponding variable pump regulator and an oil inlet of a corresponding negative flow throttling hole in parallel, and the second negative flow control loop is connected to an oil outlet of a pilot pump and a corresponding variable pump regulator in parallel and used for sending pressure signals generated by the oil outlet of the pilot pump to the corresponding variable pump regulator under the situation that the hydraulic system action signal is not received. According to the hydraulic negative flow control loop and method and the executing mechanism and system, the displacement and the output pressure of the variable pump are reduced to be minimal at the same time under the situation that the hydraulic system action signal is not received, and complete unloading of the system is achieved.