Mutton is one of the important meat food sources for nomadic people in northern China. In the process of formation and development, the custom of eating mutton in the northern grassland has been increasingly close to the dietary culture exchanges with Central China, Central Asia, West Asia, South Asia and other regions, enriching its own cultural connotation and forming a regional and national mutton eating culture. A dietary pattern of eating mutton that use rice, noodles and other traditional grains from Central China as grits, use carrots, black beans, onions, spinach and other exotic vegetables as the auxiliary materials, use ginger, cinnamon, orange peel, pepper, nutmeg and other spices is formed. This paper focuses on the extraterritorial elements of the mutton eating culture in the grassland regions of northern China in the historical period, discusses the spreading process and history of the dietary cultures of Central China, Central Asia, West Asia in the northern grassland regions, summarizes how the northern grassland regions absorb the external dietary culture and the influence of the external dietary culture on the dietary customs of northern nomadic people.