Abstract: The integrated energy system is an important carrier for realizing the goal of "double carbon", and economic and efficient collaborative allocation of multiple resources is the prerequisite for realizing sustainable and healthy development of the integrated energy industry. At present, the integrated energy system configuration models mainly aim to minimize costs but seldom consider return on investment. This may prolong the payback period, which leads to lower capital turnover efficiency and increased financial risks. Consequently, this paper firstly proposed the capacity value function of the integrated energy system, which takes the allocated resource capacity as the independent variable and the reduced running cost as the dependent variable to realize the analytic expression of the multi-resource capacity value. Then, a multi-resource collaborative allocation model based on fractional planning theory was established, which aims to maximize the return on investment and construct the best cost-effective allocation strategy. Further, the fractional planning problem, which is difficult to solve, was linearized by the variable substitution technique, and a decomposition iteration algorithm was proposed, to realize the outer approximation of the capacity value function and the efficient solution of the multi-resource collaborative allocation strategy. Finally, by simulation analysis and comparing with the cost minimization method, the effectiveness of the proposed method is verified.