Supplier selection negotiation is a challenged, complex, and nondeterministic problem. To solve the problem well, it is necessary to develop an intelligent system for negotiation support in supplier selection process. Reinforcement Learning (RL) is a powerful algorithm which can be used for the price offer in supplier selection negotiation with the aim of maximizing the demander's profits. In this paper, we formulate the supplier selection as a RL problem. States, actions, and reinforcement function are defined in this problem. In the next step, we compare the proposed RL method with traditional method.