The past 300 years is a fixed expression frequently used by scholars of the Republic of China in the writing of Qing history, and it is a narrative mode generated under the specific historical environment at that time. Liang Qichao was the first to define the history of "the past 300 years", endowing it with connotations such as opposing the feudal view of history, advocating ideological emancipation, and serving social reality, trying to provide reference and guidance for the social development at that time, which had a profound impact on the writing of Qing history in the period of the Republic of China. He is the actual founder and promoter of this narrative mode. "The past 300 years" historical narrative widely appeared in many research fields such as academics, politics, diplomacy, and religion at that time, establishing a brand-new historical interpretation system, which marks the awakening of modern Chinese intellectuals. The emergence of the narrative mode of "the past 300 years" is not only influenced by the strong input of modern Western culture and the debate between Chinese and Western cultures, but also has a great relationship with the "anti-Manchu" trend of thought that emerged in the late Qing Dynasty and the early Republic of China. "The past 300 years" contains the antecedents and consequences of the history of the Qing Dynasty. It stretches and broadens the rise and fall of the Qing Dynasty, the change of thought, traces the origin, and eliminates the historical estrangement caused by the change of dynasties. It clearly shows the complete picture of the occurrence, development, prosperity and decline of the history of the Qing Dynasty, which is clearer than the narrative context of writing of dynastic history. The narrative mode of "the past 300 years" opposes the feudal historical view with the bourgeois enlightenment thought, impacts the traditional "Dynastic Theory" narrative with the "Period Theory", emphasizes the overall research method, pays more attention to the history, reflects a way for scholars to think and solve the problems of Chinese social history at that time, and represents a progressive historical view. Although this narrative mode was influenced by Western culture, it turned to Chinese history as the standard and reflected on Chinese academic, political and social with historical initiative spirit. It is a new exploration of the research paradigm of Qing history and provides a theoretical reference for the writing of contemporary Qing history. It should be pointed out that the connotation of "the past 300 years" has changed significantly with the development of the times. When contemporary scholars use "the past 300 years" to write the history of the Qing Dynasty, it is necessary to redefine its time limit, research scope and theoretical connotation.