Abstract: Based on the optical thin film mechanism and optical constants inversion in wide frequency domain,the design of Al based CCAl composite thermal control thin film is realized by MATLAB programming technique.The design results of three typical thermal control thin films show that thermal control parameters of the film system can be adjusted in a wide range.The solar absorption/emittance ratio is between 0.16 and 7.14,which covers most of the applications.In addition,its good protective performance and direct deposition characteristics provide support for wide application.