Big data "affinity" violates the principle of honesty and credit. It is a new type of price fraud that infringes consumers' right to know and fair trade. On the theoretical level, our country interpreters regard big data "affinity" as a price discrimination behavior, apply the concept of “price discrimination” in economic theory to legal subject and increase academic controversy and problems in practice. On the practical level, the price legal norm system that regulates the "affinity" behavior of big data is too broadly extended because of the unclear definition of price fraud, and it is difficult to apply due to excessive competition. Clarify the price fraud attribute of big data "affinity" behavior, and legislate the connotation of price fraud and its constituent elements to eliminate the chaos of law and competition, which is to effectively regulate big data "affinity" behavior and promote the healthy development of China's data and information industry.