This paper examines the power and medium that involved in cultural changes such as the spread of the Indian styles that emerged in the Tang in the late 7th century. Many scholars focused on monk Xuanzang, who returned to Chang’an in 645 with seven Buddha statues after a 17-year trip to India, as the figure who led the spread of Indian styles in the 7th century. In this study, I critically examined this view through related records of the time and the King Udayana statues produced in the Luoyang in the late 7th century. Furthermore, I argued that the dissemination of paintings from India by diplomatic missions such as Wang Xuance played a more important role in the spread of Indian styles. Among the many materials they have painted in India were the Vajrasana Buddha Statue at Mahabodhi Temple in Bodh Gaya, and the stone of Buddha footprint. The two Buddhist icons were distributed to East Asian countries such as Korea and Japan as well as Tang in the late 7th century. Another medium to look out for regarding the trend of Indian styles since the late 7th century is the Xiyu-zhi. This book was compiled by King Gaozong's order in 666, and it was a 100-volume book that contained objects from all over the West in writing and painting. Xiyu-zhi seems to have been circulated immediately after its compilation. A book summarizing the contents of Buddhist sites contained in Xiyu-zhi was immediately made by a monk. In addition, as shown in various existing 'Miraculous Buddha images', it spread widely to Dunhuang and Japan. As such, the Buddhist paintings drawn by the official diplomatic delegation of the state in India and the official book Xiyu-zhi played an important role in the trend of the Indian styles of the Tang Dynasty, which began in the late 7th century. In other words, the emperor power of the Tang Dynasty was the power that led to the trend and spread of the Indian styles.