Abstract: With the rapid development of the Internet, online retail industry presents a typical phenomenon of commercial agglomeration, but there are great differences between traditionally spatial commercial agglomeration and non-spatial commercial agglomeration based on Internet. By analyzing and mining the corpus of depth interview with consumers and merchants, this paper constructs the system dynamics model of non-spatial commercial agglomeration based on Internet, also the simulation and sensitivity analysis is carried out. The results prove that: there are 3 positive feedback loops and 6 negative feedback loops within the system of non-spatial commercial agglomeration based on Internet, forming the driving force and constraint force of the system; the overall trend curves formed by evolutionary of the cluster scale of consumers and merchants are all “S-shaped”, the network switching cost of consumers，word-of-mouth of platform and so on have an impact on the scale and the speed of agglomeration, while platform′s support for merchants, the merchants′ cost of entering platform and so on only have an impact on the speed of agglomeration but not the scale. Therefore,the value of exogenous variables that affect the speed and scale of platform agglomeration is directly related to the platform website,and the intervention in these variables is of great significance to the platform commercial website.

Key words: commercial agglomeration, Internet, system dynamics, non-spatial agglomeration