Abstract: Digital twin technology is used to study the robotic mobile fulfillment systems (RMFS). The digital twin modeling approach corresponding to RMFS is proposed and an example of the digital twin is presented. Experimental results shows the mechanism of AVs' deadlock and conflict can be better represented by the proposed digital twin technology. Moreover, the digital twin is able to reconfigure with the reconfiguration of physical RMFS, which is called symbiont. It is believed that the proposed digital twin technology can help gain a better understanding of physical RMFS and help the e-commerce enterprises to utilize RMFS better.