Abstract: Aiming at the multiple constraints brought by new deep space exploration missions to satellite development, this paper proposes a forward design method for satellite overall accuracy. The method uses hierarchical decomposition of overall accuracy modeling to transform the satellite structural design model into a tolerance propagation model with clear transmission paths, providing effective input for system accuracy probability analysis. Subsequently, the Monte Carlo method is employed to evaluate the system accuracy probability, identify the relevant paths and tolerance sources of key indicators, and quantify their contribution degrees, thereby providing a basis for subsequent tolerance optimization and manufacturing. This method provides direct and quantitative design input for achieving high-accuracy and complex-coupling overall accuracy optimization.