Abstract: The steel tubed reinforced concrete (STRC) column joints are strengthened using built-in section steel. To clarify the position of control section and compression-bending capacity of the STRC column with built-in non through section steel in the joint, the quasi-static test and finite element simulation were carried out on the STRC columns with different lengths of built-in section steel and the comparison specimen without section steel. The mechanical mechanism and bearing capacity of the specimens were analyzed, and the effects of the length of section steel and confinement of steel tube were discussed. The results show that with the increase of the length of the built-in section steel, the failure section tends to transfer from the steel-concrete transition section to the column root. Increasing the diameter thickness ratio of steel tube will reduce the compression-bending capacity of steel tube and transition section and then affect the location of failure section. Based on the test and finite element analysis results, the calculation models of compression bending capacity of the column root and transition section are proposed, and the determination method of critical length of section steel is established. The research results provide a theoretical basis for the design of STRC column and joint with built-in non-through section steel.