In the modern society, we regard cultural heritages as symbols of the history, which carry the mission of inheriting ethnic cultures. Tourists usually won’t miss the chance to visit these antiquities when they travel around the world. Thus, many countries are trying hard to protect cultural heritages and bring them back to life through the development of tourism. Meanwhile, the concepts of the heritage revitalization and patrimonialization have appeared. It’s not only in Taiwan and nor in France, these ideas are spreading in many parts of world and are considered as principal elements of tourism. In 2014, I came to Carcassonne for visiting a friend, and was amazed by the charm of its castle with 2 thousand years of history. When walking through the alleys between the walls, I can see that the old monuments, like towers and churches, were still there. In the meantime, I could also see the modern changes, like restaurants and souvenir shops. Then I noticed that these two symbols of different periods of time can be put together harmoniously. At that moment, a question came into my mind: how was the castle transformed into a historical heritage and a tourist site at the same time? In order to find out the answer, in this thesis, I will discuss and analyze the concept of < heritage (patrimoine) > and the execution of < patrimonialization > in three chapters. In the first chapter, I will try to find out the changes of the functions of the castle and its role throughout the history. According to the recordation, from the 6th century B.C, the Carcassonne Castle was sequentially governed by the Romains, the Wisigoths, the Arabians and the Kingdom of France. Then, because of signing of the Treaty of the Pyrenees, it lost its strategic role and was almost destroyed. But thanks to local people and writer Merimée’s defense, the castle was retained. Later the government sent the architect Viollet-le-Duc to execute its reconstruction. In the second chapter, I will use theoretical methods to analyze the definition and the origin of < heritage (patrimoine) > and execution of < patrimonialization >. I will also explain how the reconstruction of the castle and its changes throughout the time show the achievement of these theories, that is to say, how the castle can have two identities at the same time. In the last chapter, I will focus on the influence of tourism. I will firstly analyze the changes of functions of several buildings before and after the reconstruction. Then I will move on to the advantages and disadvantages of the tourism and its benefits of these years to underscore the importance of heritage to the tourism. Via this research, on the one hand, we can see the changes of the practical functions of the castle ; on the other hand, the mental role it plays also transforms along with the development of thought. Besides, nowadays, its two identities existing at the same time, the cultural heritage and the tourist site, need a balance between them so as to keep the sense of harmony. This not only requires the contribution of local people and of the government, but also concerns every tourist’s effort to protect this cultural treasure.