Extensive researches into the meaning of the famous Tang poem On Mission to the Frontier have achieved success for years, but it still remains several questions. On the one hand, On Mission to the Frontier has been selected for different poetry anthologies from the Tang Dynasty to the Qing Dynasty. And it brings four different texts, which are “銜命辭天闕”, “向”, “鴻” and “吏”, and the reason why they come into being should be figured out. On the other hand, the interpretation of “屬國” and “孤煙” and the main idea of On Mission to the Frontier are not clear and definite, so they also need to be differentiated and analysed.