The invention relates to a complete machine dynamic stiffness testing system for a numerical control machine tool and belongs to the field of machine tool vibration stiffness testing equipment. The system comprises an excitation subsystem, a force acquisition subsystem, a displacement acquisition subsystem, a data acquisition front end and a data processor, wherein the output end of the excitation subsystem, the input end of the force acquisition subsystem and the input end of the displacement acquisition subsystem are respectively connected with a to-be-tested position of the machine tool; and the output ends of both the force acquisition subsystem and the displacement acquisition subsystem are connected with the data processor by the data acquisition front end. According to the testing system, a stable dynamic excitation force can be provided; dynamic displacement of a spindle of the machine tool relative to a working table can be accurately measured; and the testing system has the characteristics of accuracy for testing, simplicity for operation and the like.