As an important painting theorist in the Period of Eastern Jin, Wang Wei was born a bit later than Zong Bing, while Wang's On Paintings and Zong's Preface to Landscape Painting are both the earliest theories of Chinese landscape paintings. Their theories about painting have a lot in common and deserve some comparative research. This article is divided into the following four sections: Wang Wei's biography; the purport of On Paintings; the aesthetic meaning of Preface to Landscape Painting; and the conclusion.The brief biography of Wang Wei is to make the readers understand his status in the history of Chinese painting. Regarding the purport of On Paintings, its writing is succinct but rich, and the text is quoted and paraphrased to help the readers develop the most direct first contact with the author. The aesthetic meaning of On Paintings is the main point of this article. Based on its purport, the writer proceeds along four sections to discuss respectively the following issues: the same origin of calligraphy and painting, the existential origin of painting, the artistic philosophy of painting and the aesthetics of painting. Due to the historical distance, the manuscripts of the original text are inconsistent in many ways, which leads to many differences in interpretation. Here we address the disagreements between the different copies to facilitate the reading of its meaning. In the section of the conclusion, the meaning and value of On Paintings are confirmed and upheld.