The growing technology has changed the form of advertising and user behavior. Recent years, the amount of personalized advertising is on a steady rise. Personalized advertising is based on a method called retargeting to tailor the advertisements to individual consumers by inferring their interests and preferences.However, there are still many deficiencies in personalized advertising that reduce the user experience. Understanding the attitudes of users and companies to personalized advertising can help improve these deficiencies. Hence, the purpose of this study is to compare different opinions regarding personalized advertising from Chinese consumers and companies towards Taobao respectively.This investigation uses a case study method to study the purpose. Taobao is an e-commerce platform with a high frequency of personalized advertising and has a great impact on China. Therefore, Taobao has been chosen as our case. First the background of personalized advertising is introduced, and then personalized advertising in Taobao is described. The different opinions of both consumers and companies are studied. In general, consumers have a positive attitude towards personalized advertising. However, there is a need for improvement in terms of privacy, trust and effectiveness. For companies, the effect of personalized advertising is satisfying, but the price makes is difficult for them to afford it.