Abstract: Integrated energy service (IES) is a key development area of value-added services for power grid enterprises. The study on the investment decision-making method with consideration of uncertain factors can effectively improve the investment benefits of power grids. From the perspective of integrated energy investors, based on interval linear programming and technique for order preference by similarity to ideal solution (TOPSIS) an investment decision-making method for industrial park type of integrated energy system was proposed. Firstly, the uncertainty of load and energy price was described by interval numbers to construct an interval number based uncertainty programming model for integrated energy system. Secondly, solving this model, the annual comprehensive cost and annual carbon emission cost were obtained. Thirdly, overall considering the economic index and environmental index of the industrial park, TOPSIS was chosen to rank multiple investment planning options, then planning as a whole, the optimal plan that synthesized economy and environmental protection was screened out. Case study results show that the proposed method can effectively assist the Integrated energy company to make rational investment decision.