Summary: The phenomenon of store brands introduced by large-scale platforms is becoming common, and manufacturers should carefully choose the business mode of selling national brand (NB) products via platforms. Considering big-data marketing, we examine the sales mode selection in a platform-based supply chain based on the strategic interaction between the business mode decision and store brand decision. By continuous dynamic game theory, the strategies and performance under different modes are solved. We find that given the store brand (SB) decision, the business mode adopted by the manufacturer depends only on the commission rate, which is high for reselling and low for agency selling. Given the business mode, under reselling, whether the platform introduces SB depends only on the brand preference, i.e., SB is introduced when the preference for NB is low. While under agency, he introduces SB in the general or relatively passive situation, depending both on the commission rate and the brand preference. In addition, four equilibrium sales modes are obtained based on the strategic interaction. In order to achieve a win-win-win situation in profitability among the manufacturer, the platform and the platform-based supply chain, the manufacturer should adopt agency selling and the platform forgoes introducing SB when both the commission rates and NB preference are low.