The trilogy of missing the starry sky refers to three poems written by the poet Sun Gan, namely "Valley at dusk", "Starry sky and agarwood" and "Starry sky and half a tree". The themes of these three poems are natural scenery and philosophy of life, which express the author's deep thinking about life, love and time. Among them, The Valley at Dusk describes the scene of the valley at dusk, emphasizing the ruthlessness of time and the shortness of life. Starry sky and agarwood express their desire and pursuit for beautiful things through the contrast between starry sky and agarwood; Starry Sky and Half a Tree discusses the meaning and value of life with the background of the loss of half a tree. These three poems are regarded as Sun Gan's representative works and the classics of China's modern poems.