With the progress and development of society, the facility configuration of existing highway service area is gradually difficult to meet the diversified functional needs of the passengers. To realize the purpose of improving the facility configuration suitability of existing highway service area, the evaluation index system and model suitable for the facility configuration of existing highway service area were researched. Firstly, from the three aspects of facility status, service level and user experience, the evaluation index system covering 11 indicators, such as facility completion rate, average congestion degree, price satisfaction, was constructed. Then, an improving cloud model was presented, which used AHP, order relation analysis method, entropy weight method and DEMATEL to acquire the subjective and objective weights, and least squares method to confirm the optimal combination weights. Finally, calculating the integrated evaluation cloud by forward and reverse cloud generator for R a service area in Sichuan Province, and the evaluation level is "good". The results indicat that it is feasible to evaluate the suitability of existing highway service area.