There is a close natural connection in tourism and Convention & Exposition (C&E) since they are mutually affected and promoted. This study attempts to theoretically analyze the tourism effect and marketing tactics of the C&E industry. To do this, the inductive method and value train theory are introduced to analyze the supply and demand of tourism. Findings reveal that not only can C&E produce positive influences such as synergistic effect and cluster effect on tourism, but also negative result which is characterized by spillover effect. Taking Shenzhen city of China as an example, several marketing strategies are found. It is concluded that such strategies on C&E and events exhibition can meet the needs of Shenzhen, and improve the tour image of this city, so as to help expand its influence on tourism.