With the continuous growth of the national economy and the continuous breakthroughs in Internet technology, a new era of big data has come. Although China’s e-commerce industry started late, it has seen rapid development In recent years, it has gradually become an important driving force for China’s economic development. In e-commerce, the application of big data lies in mining useful data information for analysis, to reasonably predict the future market, reduce costs, and maximize profits. In modern enterprises, effective supply chain management is a source of profit that can not be ignored. It can produce great profit benefits, which is almost the most important for current e-commerce enterprises. At the same time, the Internet and informatization of supply chain operation is convenient for enterprises to analyze the cost of each link of the supply chain in combination with big data and make favorable decisions. This paper uses supply chain cost control theories, takes PDD as the research object, analyzes the current situation of its supply chain cost control from all links, finds existing problems. Then relevant thoughts & suggestions in the big data context are put forward, including sharing data info, maintaining supplier relationship, using user portraits for consumption stimulation and rational marketing cost planning, eliminating the “copycat” impression and maintaining customer relations, absorbing management talents and rationally allocating personnel for better cost control and profit improvement.