Compression behavior of confined concrete was discussed. Lateral restriction mechanism of steel tube confined concrete and stirrups confined concrete was analyzed. Based on the twin shear unified strength theory and a series of experimental results， the uniform formulas to determine peak stress and peak strain were established and validated. Combining the Chinese current specification， practical stress strain models of confined concrete were proposed and compared with experimental curves. Results show that the proposed formulas to determine peak stress and peak strain are accurate， and the proposed stress strain models are more accurate， simple and useful. The proposed stress strain models can be feasible in the nonlinear analysis of confined concrete.