Archaeological evidence and various historical documents indicate that Chinese were aware of the lands beyond the mountains of the West, especially Iran. This article argues that Iranians had a great role in transferring Iranian religions as well as some other religions such as Christianity to China. As such, the transfer of medical knowledge had had occurred along with transferring those religions and beliefs.As it is the case now, in the past, business relationship between countries and different ethnic groups played a great role in knowledge transfer between nations. By reviewing the existing historical documents, library resources and archaeological findings, show that the extensive trade exchanges between Iran and China, lead to not only cultural exchange and religious beliefs but also the transfer of medical beliefs, knowledge and practices to China. This happened by the Iranian religious envoys as well as non-Iranian religious missionaries. In conclusion, this knowledge and technology transfer had an impact on the flourishing Chinese medicine.