In order to meet the higher temperature resistance requirements of spacecraft solar wing substrate for future deep space exploration， this paper introduced a new forming process of solar wing substrate： co-curing of polyimide film and carbon grid panel. The study focused on the stripping performance of the polyimide film and the grid panel， the tensile performance of the grid panel， the bending performance of the honeycomb sandwich structure， and the temperature resistance of the co-cured substrate was made comparison of performance of samples by traditional process of using J-133 adhesive to bond polyimide film. The results showed that the peel strength of the co-curing polyimide film was about twice that of the traditional process， and the mechanical properties of the film were more than 87% at 140℃， showing good temperature resistance.After the thermal vacuum test from -100℃ to 140℃， the appearance quality and various properties of the co-cured substrate passed qualification， which met the needs of the solar wing substrate to withstand the space environment of 140℃ and below.