1. Tragedy is the most prominent aesthetic feature of frontier poems in Tang Dynasty. This is because frontier fortress poetry, as a kind of poetry, has its unique theme and emotional tone. "Looking at Hu Tianyi from a distance, the clouds are light and the wind is light, the rain is rustling, the sound of herding horses is broken, and the wind is curling up and singing a few songs" (Gao Shi's Preface to the Yunnan Pavilion Banquet with Shi Yuling), "The bones are horizontal and desert, and the soul is chasing the cornices; Or negative Ge Waishu, murderous male edge; The life of fighting (Zhong Rong's General Comment on Poetry), recruiting talents (Wan Li's Ten Years' Battle of Tiger City), Liu Changqing's Tired Soldiers and the Red Horseshoe's Return (Cen Can's Send Zhang Dawei East) all have tragic connotations.
2. Frontier poets integrate these themes into frontier poems, which makes frontier poems have a tragic atmosphere. The lofty passion of "recruiting people" shown in this tragic atmosphere is the emotional core of the tragic beauty of frontier fortress poems.