Sogdian merchants played an essential role in the commercial and cultural activities between the Tang dynasty and other states in the west of Tang, along the Silk Road. Based on the conditions for the Tarim region to be able to perform a role in the commercial transfer station and the well-established advanced monetary and postal system, the article discusses how the Tang court's policies influenced the Sogdian commercial system that the influence was mainly in three aspects: i) Tang court intentionally introduced Sogdian merchants and helped Sogdian merchants to spread; ii) The household registration of Sogdian merchants and endorsement by Tang court offered Sogdian merchants significant opportunities to earn profits from trading with Tang court when Sogdian merchants monopolized the trade between Tang dynasty and western states; iii) The fusion of Sogdian people into Han people and Sogdian people's entrance into the political system of Tang court enhanced the Sogdian merchant's commercial networks. Finally, the article concludes: The deep fusion of ethnic groups of Han people and Sogdian people was the promoter of the prosperity of the Tang dynasty, and it again made the Sogdian commercial network thrive.