Abstract.In the field of artificial intelligence and computer science, Dynamic Epistemic Logic (DEL) is often used to model the knowledge, the inference in multi-agentknowledge, the action reasoningin game, and so on. This is because, unlike the general static epistemic logic, the dynamic perception can express the knowledge update in the multi-agent interaction. This paper,after analyzing some kinds of knowledge involved in the multi-agent interaction, proposes a Knowledge Sharing System (KSS) that extends the epistemic language with a new operator of 'knowledge sharing' for bi-agent interaction. Its soundness and completeness will beproved, and some properties about it will be analyzed in this paper.This system offers a clear presentation of how an agent gets to understand the other's intentions through the action of "sharing", which allows further interaction.