Nowadays, people are in a competitive environment. Consumers are given more options because of the development of mass media and technology. How to compel consumer’s attention and stimulate their purchase intention is highly concerned by many companies. Some of them hire advertising endorsers to promote products and boost selling. In other words, promotion is a popular method proposed by companies to increase consumption. Under this premise, this research takes McDonald’s as the example for studying how advertising endorsers influence the purchase intention. Base on the research motive and purpose as well as documents reviewing, the five hypothesis are: 1. the credibility of advertising endorser has a significant impact on consumer’s purchase intention toward McDonald’s products; 2. sales promotion can significantly affect purchase intention toward McDonald’s products; 3. the demographic diversity develops different viewpoints towards credibility of advertising endorser;4. the preference of sales promotion can be distinguished with demographic diversity; and 5. McDonald’s products consumption also can be distinguished with demographic diversity. Totally 360 questionnaires were distributed and 351 usable questionnaires were retrieved by quota sampling. Various statistics gather by SPSS12.0. The research is concluded with the following points, the credibility of advertising endorsers and sales promotions significantly affect purchase intention; the agreements of expertness of endorser credibility significantly differ from the education level of customers; the preferences of price discount significantly differ from age, marriage, and family composition; purchase intentions significantly differ from age, occupation, personal income, and marriage.