The present study focused on “Tang Lu Shu Yi”, the very code representing the feature of the rule of law in the Confucian-legalistic State of imperial China. As the earliest and most complete code in existence, it was the mature form of the Chinese legal system. According to those remaining decrees and administrative practices before the An-Shi Rebellion, our research explored the system design of law in Tang dynasty via how the law responded to the spread of folk religions, dealt with folk gatherings and associations and managed people's daily travel and communication. From the early to the prosperous Tang Dynasty, the cultural exchanges between traditional China and foreign countries and people-to-people communication were dynamic and active. Given those, to maintain political security and social stability, rulers of Tang Dynasty took advantage of legalization and administration to coordinate with the cultivation of orthodox ideology, which alleviated the pressure of cultural exchange, integrated the heterogeneous cultures and eventually managed civil society communication. It’s the very pursuit of hierarchical order and traditional value that behind all these written laws and flexible policies.