Abstract: There are three different kinds of testing cells for measuring the rock stress in our country to-day, such as, borehole triaxial-strain gauge, borehole diametral deformation gauge and borehole bottom strain gauge. This paper suggests a new transformation which can put their data processing methods into an unit form, and it may be used by mathematic statistical method through electronic computer to determine the stress of rock mass, which is more reliable and convenient. At the same time, this paper analyses and compares the measuring precision and the law. of the precision variation between the different colls.