Abstract: In order to study the causes of producing self-excited vibration and the ways of reducing draft force in the process of subsoil cultivation, based on the principle of mechanical vibration and the technology of electric signals measurement, the parameters of evaluating the self-excited vibration subsoiler system composed of 1SQ-127 model bulk subsoiler, such as cultivating depth, soil resistance and tractor draft force were measured by electric measuring instruments and equipment. The data collected from the experiment were processed by computer and the transient characteristics of “trctor-subsoiler-soil” system were analyzed. The ways of reduction of draft force and energy-saving of subsoiler were studied and a new method for reducing soil resistance by self-excited vibration subsoiler was put forward.