Apart from the three revenue sharing parameters, the other parameters of the revenue sharing contract (RSC) in a low-carbon supply chain cannot be precise values in most cases. As a result, adopting the RSC will cause challenges in the low-carbon supply chain. In this paper, to calculate the value of the revenue distribution parameter, a decision method based on multiple index is put forward. First, we construct an index system of revenue distribution based on the viewpoints of cost, efficiency, and satisfaction. Second, we propose the third-party participation (TPP) mechanism and the group analytic hierarchy process (GAHP) decision-making approach according to the premise that “heteronomy is better than self-discipline.” By the use of the case of company “A,” we demonstrated the applicability and practicability of the decision-making approach. The main contributions of this paper are twofold. First, we surveyed 22 experts and set up the 43 indexes, while also constructing the analytical hierarchy process matrix and explaining each index in depth. Second, the TPP mechanism and the GAHP method are used to calculate the value of each index and their sensitivity to the decision-making by the software of Yaahp12.0. Overall, this research can help the decision-makers of low-carbon supply chain in determining the ratio of revenue distribution and improving the applicability of revenue sharing contract.