Abstract: To investigate the seismic performance of the proposed thin concrete encased steel T-shaped column, a refined finite element model of the specimen was established by ABAQUS finite element software. After verifying the rationality of the model, 20 finite element models were established with axial compression ratio, stirrup spacing, concrete cover thickness, steel flange thickness and longitudinal reinforcement diameter as parameters, and the influence law of parameter variation on seismic performance was discussed. Results show that as the axial compression ratio increases, the plumpness of hysteretic curve decreases. When the axial compression ratio reaches 0.6, the ductility decreases by 35.37%, the equivalent viscous damping coefficient is less than 0.3, and the cumulative energy consumption decreases by 61.69%. As the stirrup spacing decreases, the ductility and energy dissipation capacity increase. To ensure the seismic performance of the specimen, it is recommended that the stirrup spacing is 100 mm. The ductility and energy dissipation capacity cannot be improved by increasing the thickness of the concrete cover. When the thickness of the steel flange is increased to 20 mm, the ductility is increased by 41.99%, the load bearing capacity is increased by over than 18%, and the cumulative energy consumption is increased by 90.46%. When the diameter of the longitudinal reinforcement increases to 20 mm, the ductility increases by 57.40%, the load bearing capacity increases by more than 41%, and the cumulative energy consumption increases by 117.42%.