On the basis of tourism authenticity theory and field investigation and analysis of Lijiang ancient city, the paper had explored tourists’ tourism authenticity, and further revealed the inner relation between tourism authenticity and tourism motivation of ancient cultural cities. It was found that ancient cultural cities generally had the highest objective authenticity, followed by existential, constructive and post-modern authenticity. As for tourism motivation, motivation of knowledge function, of reward maximization, of punishment minimization, of self-esteem and of self-fulfillment presented to diminish progressively. Relationships between four types of tourism authenticity and five types of tourism motivations also varied from each other. It had enriched empirical quantitative research results of domestic tourism authenticity in theory, and provided application value for the research on realistic tourism market and planning activity based on tourists in practice.