This paper examines the influence of external information on their purchase behaviour of GM food. Data are gathered from auction experiments. The results show that external information affects the purchase behaviour of consumers. Participants who receive single negative information from environment groups discount GM foods more highly than those who receive other information combinations. The positive information provided by biotechnology companies can increase participants' bid price of GM food compared to negative information. Objective information provided by the third party organizations can not significantly affect the consumer behaviour of GM food in this study. These results have implications for information policies.