“西口”作为与“东口”张家口相对应的北方重要商贸关口,近年来受到各界人士的关注。文章在进行实地考证的基础上,通过对相关史料的研究得出最早的西口即是当今右玉县杀虎口的结论。作者还从杀虎口特殊的地理位置入手,就这一重要关口的设立、在国家财政和北路贸易中的重要历史地位以及由此逐渐形成的“西口文化”现象进行了阐述。 “West exit ” as the northern important trade mark corresponding to “East exit ” Zhangjiakou, in recent years by people of all walks of life. Based on the textual research on the field, the article draws the conclusion that the earliest west mouth is the current kill Yuhukou in Youyu County through the research on related historical materials. The author also starts from the special geographic location of Shahukou and elaborates on the establishment of this important juncture, the important historical position in the state finance and the North Road trade and the gradual “Westward Culture” phenomenon.