In the early stages of the product design, multiple principle solutions are obtained through function solving, and a large number of conceptual schemes are generated by combination. Therefore, scheme decisions are important factors in the concept design. The existing decision methods primarily focus on the satisfaction of economic needs, and the impact of technical indicators on the technical performance of the scheme, while ignoring the conflict of needs between the two subject objectives in the decision process. Actual decisions need to be weighed against each other’s expectations. In addition, the qualitative interactive objectives will affect the decision direction of the conceptual scheme. Herein, we propose a relative equilibrium decision approach for concept design based on the fuzzy decision-making trial and evaluation laboratory-cooperative game model. This model is primarily divided into two parts. One is to solve the impact relationship between the objectives, and the objectives’ weights are obtained through fuzzy decision-making trial and evaluation laboratory (FDEMATEL). The second is to incorporate the objectives’ weights and impact utility into the cooperative game model, to reasonably weigh the relative interests of the two subjects to meet the corresponding interactions, and to obtain the scheme with the largest overall design desirability. Finally, the case study proves that this decision model can identify the optimal scheme. This model is proven to be robust by comparison with other methods.