The case of Sina Weibo v.Maimai reflects that in the era of big data，enterprises are increasingly paying attention to the possession and use of data，and the legal protection of big data is increasingly important.By analyzing the Sina Weibo v.Maimai，it can be concluded that in the current three ways of protecting big data in China，commercial secret protection has comparative advantages with clear rules and strong protection.Because most of the information in big data comes from the public domain，however，it is controversial whether it can constitute a trade secret.In addition，in the commercial secret lawsuit，the distribution of the burden of persuasion is unreasonable which hinders the protection of big data.In order to adapt to the development of the era of big data，China’s laws should clarify that big data from the public domain is secretive under certain circumstances，at the same time，should redistribute the burden of persuasion between the plaintiff and the defendant，and appropriately reduce the burden of persuasion of the right holder.