With the continuous integration of "Internet +" and traditional industries， more and more small and medium-sized enterprises with insufficient e-commerce operation ability choose to enter the e-commerce industry by means of e-commerce service outsourcing. E-commerce agent operation service enterprises are facing not only opportunities but also fierce competition and challenges at the same time. In order to improve the competitiveness of e-commerce agent operation service providers and enhance their core competence building， an evaluation index system of the competitiveness of e-commerce agent operation service providers is constructed from seven aspects of enterprise comprehensive strength， agent operation technology， agent operation service items， agency operation service quality， human resources， enterprise reputation， and development potential. In view of the situation of numerous evaluation indicators and complicated subjective and objective factors， this paper establishes a multi-attribute comprehensive decision-making method combining DEMATEL and ANP. Firstly， DEMATEL is used to analyze the relationship among evaluation indicators and draw the quadratic diagram of influencing factors. Secondly， ANP network of importance and relevance of competitiveness of e-commerce agency service providers is constructed， and ANP method is introduced to calculate the global weights of each indicator and mix them with the adjusted comprehensive matrix. Finally， by analyzing the mixed weights， identify the management system， financial status， historical performance， service concept， strategic planning as the key factors affecting the core competitiveness of e-commerce agent operation service providers， this paper develops targeted countermeasures to cultivate the core competitiveness of enterprises.