Abstract: Based on the Tsai-Wu’s tensor polynomial and test of grouted concrete masonry, a cubic polynomial failure criterion equation involving three stress parameters under plane stress state, is presented in the paper. By using the stress transform equation of material mechanics, the above equation can be deduced into one depended on two principal stresses and its angles. Using experimental data and the least-squares method, the parameters of the grouted concrete block masonry have been calculated, and the cubic polynomial failure criterion equation applicable to engineering is obtained, and the 3D failure surfaces and the 2D failure curves are gained. The calculated results show that the calculated curves are in a good agreement with the experimental results and used for the design and numerical analysis of grouted concrete masonry structures.