Agent X is an agent which is designed for ANAC2015—The Sixth International Automated Negotiating Agents Competition. In this paper, we will show the two main strategies—Agreement Behaviour and Conceder Behaviour of Agent X. Although a lot of agents pay more attention to the individual utility, Agent X is an agent which thinks highly of the social welfare. As a result, Agent X tries its best to come to an agreement with other agents before the negotiation ends. But it doesn’t mean that Agent X doesn’t care the result of its individual utility, Agent X also tries to get a relatively good individual utility at the same time.