A textual study on the newly-released Epitaph of Kang Taihe, the General of the Army of the Palace Guards in Tang Dynasty(618-907) shows that Kang Taihe, the epitaph owner, was born into a Sogdian family whose father and ancestors served in the assault-resisting garrisons (zhechong fu折冲府) of Liang Prefecture for three generations. Kang Taihe himself started as the garrison commander (shuzhu戍主) in Chiling, the forefront of the war against the Tibetan Empire.Starting from the beginning of Kaiyuan Era(713-741), he served in the court "guarding the Royal Palace for 30 years and got promoted 15 times," until becoming a high-ranking imperial army officer, i.e. the general of the army of the Palace Guards(Yulin Jun,羽林军).When there was a war in the frontier, he went to fight under the imperial edicts for many times. For example, in 733, he took part in the battle of Xue Chuyu (薛楚玉), the governor of You Prefecture, to break the Khitan. From Dunhuang document P.3885 and the Epitaph of Kang Taihe, we can see that he returned home from the end of Kaiyuan Era to the beginning of Tianbao Era (742-756), and successively held many important positions in Hexi (河西) and Longyou (陇右).In 741, he wrote a challenge letter to Tridé Tsuktsen, the Btsan-po (emperor) of the Tibetan Empire who invaded Hexi and Longyou. Kang Taihe's life is a microcosm of Hexi non-Chinese generals serving the emperor coming and going between the local area and the court.