This paper introduces the comprehensive hydraulic testing set for many kinds of hydraulic elements with hydraulic drive, hydraulic regulation and hydraulic loading. It has rational structure compact arrangement, reliable characteristics and advanced technique. In order to reduce the energy loss in the hydraulic system of the testing set, 1 ad sensing control is used. The static and dynamic characteristics of the load sensing system are analysed with the method of numeral simulation on computer. the testing witk load sensing control results show energy may be saved obviously and the heat load in hydraulic system may be reduced effectively, then testing quality is improved and the volume cf oil case is lessened. The lead sensing valve design is satisfied with simplifying structure so that it may be used reliably for the fixed flow hydraulic system of the testing set or other machines.