Based on the twin shear unified strength theory, analyzing the condition of load for the steel tube and the core-concrete under tri-axial compression, the formula of axial bearing capacity of steel reinforced concrete short column with double circular steel tubes was established and the influencing factors on it were discussed. By the comparison between the results calculated by the formula and the test results, it shows good agreement. Meanwhile, applying the formula to an engineering example, good agreement can be found in the comparison between the calculation in this paper and finite element analysis result in relevant literature. The conclusions can provide a reference for the engineering design.