"Slaves" was one of the most essential "commodities" on the Silk Road. But these "trade goods" not only have material and artistic value, like others (textiles, animals, jewelry, chemicals. ) but also were social beings that brought their languages, traditions, cultures, religions, etc., wherever they went. Therefore "slavery" had an enormous place that made cultural mixture of local peoples on the Silk Road. This paper, using Islam, Chinese, Uyghur, and Sogdian sources, tried to determine the essential elements of the institution of slavery on the Silk Road, especially in the 7-11th centuries.