Tang Dynasty's legal culture proves to be the culmination of ancient Chinese legal culture. It not only enjoys a relatively complete legal system, but also absorbs traits of morality, etiquette, fairness and justice into their articles. Law of Tang Dynasty shows its openness, and its Confucian culture of integration of etiquette and law embodies its tolerance. Though a representative of the prosperous Tang Dynasty culture, Li Bai was also subject to the penalty of exile (Li Bai was once sentenced to death for conspiracy, which was finally reduced to the penalty of exile). By studying the relationship between Li Bai's death penalty amnesty and Tang Law, this paper tries to explore the openness and tolerance concept of the rule of law behind Tang's legal culture.