The advantages of global sensitivity equation (GSE) method are firstly pointed out, with which an improved multiple discipline feasible (MDF) strategy based on GSE, denoted as MDF-GSE, is developed. In MDF-GSE strategy, the sensitivity of complicated coupled system is calculated using GSE in a parallel manner, which makes MDF-GSE more efficiency when optimizing complicated coupled system compared with the original MDF strategy. Additionally, the preferable performance in convergence and robustness of MDF is also inherited in MDF-GSE. A conceptual optimization of a training airplane is executed using both MDF and MDF-GSE. The results of quantificational comparison demonstrate that computational efficiency is improved dramatically by using MDF-GSE, which makes required computation cost decreased by about 86%. The optimization time, furthermore, ulteriorly reduced due to the quasi-parallel capability of MDF-GSE. It is indicated that the MDF-GSE strategy can enhance the optimization efficiency for the complicated coupled systems.