Antimony based thin film solar cells h ave many advantages such as abun dant raw materials,simple preparation method and excellent photoelectrical prop erties.The Sb₂S_3cell with wide band gap and Sb₂Se_3cell with narrow ban d gap are combined to form a tandem solar cell,which can further improve spectral ener gy utilization and enhance device performance.Based on this,wx-AMPS software w as used to simulate and optimize the Sb₂S₃/Sb₂Se_3tandem thin film solar cells. The simulation results show that in order to obtain efficient Sb₂S₃/Sb₂Se _3tan dem solar cells,the high-quality absorption layer is needed first,and the defec t state of the absorption layer needs to be lower than 10¹⁵ cm－3 bef ore the photo n-generated carrier can be fully converted into current.In addition,the modul a tion of sub-cell thickness can balance the spectral response of top and bottom c ells,which is also very important in the optimization of tandem solar cells.Ba sed on this,contour maps of performance parameters of tandem solar cells with d ifferent top and bottom cell thicknesses were shown to provide guidance for expe rimental optimization and preparation of Sb₂S₃/Sb₂Se_3tandem solar cells .Final ly,the highest photoelectric conversion efficiency of 24.60% antimony based doub le junction solar cells was obtained under the condition that the top and bottom cell thicknesses were 700nm and 2500nm respectively.Our re sults demonstrate the advantages and development potential of the novel antimony based thin-film tandem solar cells.