In order to study the influence of constraints, indenter size and other external factors on the radial compression mechanical properties of steel pipe, a cylindrical indenter was used to conduct radial compression tests on six groups of steel pipe specimens, and to compare and analyze structural deformation, bearing capacity and energy absorption characteristics.The test results show that the setting of v-shaped constraint has a significant impact on the plastic deformation mode of steel tube, which extends the contact stroke of concave buckling deformation of steel tube, and greatly improves the sealing effect of cavity on both sides of the contact point.The structural bearing capacity, the average crushing load and the total deformation energy are proportional to the Angle of the restraint body, the diameter of the indenter and the spacing of the V body, and inversely proportional to the loading rate.In the end, a new design scheme of internal blowout preventer is put forward to deal with the out-of-control blowout of oil well.