Abstract:Compared with the other methods in in-situ stress measurement,the method of CSIRO cells is more accurate and can get the three-dimensional stresses. Professor Cai Meifeng improved the accuracy of cells and the confining pressure formulation. But now,there are some errors created in the actual operation,circuit,temperature compensation and the confining pressure formulation. With comparing two kinds of cells,it is found that 13-wire cell is better in circuit and 15-wire cell is more accurate in temperature compensation. The confining pressure formulation is analyzed,and it is pointed out that the formulation derived by Professor Cai Meifeng didn¢t consider the restriction effects of the rosin layer,so it is not accurate enough in practice.