In order to study the influence of different structural parameters on the seismic performance of L-shaped columns composed of concrete-filled steel tube mono-columns connected by double vertical steel plates (LCFST-D columns), the finite element model was established and compared with the experimental results. On the basis of verifying the rationality and accuracy of the finite element model, parametric analysis about axial compression ratio, section size of steel tube, width-thickness ratio, thickness and slenderness ratio of the connecting plate, concrete strength and steel strength were carried out. The results show that when the axial compression ratio is less than 0.6, the peak force can be increased appropriately by increasing the axial compression ratio. With the increase of the axial compression ratio, the peak force decreased; With the increase of the size of the mono-column section, the peak force, ductility, energy dissipation capacity and ultimate deformation capacity can be significantly improved; With the increase of slenderness ratio, the bearing capacity decreases sharply but the energy dissipation capacity increases. The energy dissipation capacity can be improved by reducing the thickness of the connecting plate. The predicted values of the design formula of horizontal peak force was in good agreement with the experimental values, and the average error is less than 6%.