An agent can be seen as a software and/or hardware component of system which is capable of acting exactingly in order to accomplish tasks on behalf of its user. However, intelligent agent is still quite a new technology and researches in this area primarily focus on developing technologies in agent systems itself, and research works which evaluate the intelligent agent performance are few and far between. This research applies intelligent agent to B2C e-Commerce negotiation. An experimental design is then used to collect experiment data and a questionnaire is conducted to investigate the benefits of intelligent agent systems. Results show that intelligent systems do improve performance of negotiation system, in both experiment and questionnaire analysis.