Abstract: The existing constitutive model of confined concrete is not established on the direct test data,which needs to be verified and modified.In order to accurately measure the internal stress of confined concrete,a miniature large range earth pressure box is developed.The internal strain of concrete is measured by the strain gauges embedded in a resin rod.The relevant sensors are embedded in different positions inside the reinforced concrete prismatic specimens,and finally the axial compression test is carried out to obtain the real stress-strain data of the confined concrete.The stress-strain data at different positions in the confined concrete are comprehensively processed to obtain the equivalent stress-strain curve,and then the traditional constitutive model of confined concrete is modified.Through the finite element simulation analysis of the specimen,the accuracy of the modified constrained concrete constitutive model is preliminarily verified.The accuracy of the modified constitutive model and the test technique is further verified by the static loading failure test data and finite element simulation of reinforced concrete columns.