明朝自建國以來，圍堵蒙元勢力一直是邊防重務。因而，明太祖朱元璋在陝西地區，除設置陝西布政使司外，亦建立以軍事職能為主的陝西行使司，藉以協防西北邊區。土木之變後，明軍由原本機動協防河套，改為被動固守邊牆；並沿長城建構「九邊」，其中佈防在陝西地區者，稱為「三邊四鎮」，而「三邊四鎮」一詞，也成為陝西地區的代稱。整飭兵備道的出現，實與明代軍事領導體系調整有絕對關連。自仁宗洪熙元年（1425），鑑於武官疏於文墨，特遣參政、副使前往總兵官處整理文書、商榷機密，逐漸侵越其軍權，而逐漸形成以總督、巡撫與兵備道的文職軍事領導體制。成化、弘治以後，內亂外患相煎，整飭兵備道的建制，企圖為明朝穩定社稷。陝西為明朝普設兵備道中數量最多的一省，該區地廣人雜，兵備道因地制宜，使各具有其功能性。簡言之，在邊防者，用以防禦西北部族；在腹裏者，用以討伐撫民。兵備道官以文職充任，平時揆文，亂則奮武，舉凡興學教化、修葺城堡、調度戎馬與監督官吏等皆屬之。在衛所軍制敗壞後，成為明代控扼西北與平靖三秦的利器。

Since its foundation, containment of Mongolian influence had always been an important frontier defense issue for the Ming Empire. Therefore, Emperor Taizu, Zhu Yuanzhang, not only instituted the Shaanxi Provincial Administration Hall, but also established the Shaanxi Itinerant High Commandery with mainly a military function, in order to assist with the northwestern frontier defense. After the Tumu Crisis, the Ming army had changed from a dynamic force guarding the river bend to a passive defense force adherent at the border. The ＂Nine Border Districts＂ were also built along the Great Wall. Among these, the defensive forces garrisoned in the Shaanxi area were called the ＂Three Districts and Four Towns＂ Shaanxi was the province with the greatest number of military defense circuits in Ming Dynasty when such circuit was generally instituted. The province was expansive and diverse, and the military defense circuits adopted measures according to local conditions, each serving their unique function. In short, those at the border were used for defending Mongolian and other tribes; those in the inland were used for suppressing rebels and pacifying the people. As civilian officials who understood military affairs, the military defense circuit officers might work on paperwork in peacetime, and took up military work in turmoil; their responsibilities ranged from education, renovation of fortresses, deployment of army to supervision of government officials. After the corruption of the Wei-suo (commanding stations) system, it had become an effective tool for controlling the northwestern area and suppressing chaos in the Shaanxi area in the Ming Dynasty.