For the condition that the downstream retailers have more information than the upstream manufacturer in the channel, the principal multi-agent model is structured based on the channels practice firstly. Then, the retailers’ fairness preference is considered, fairness preference model of Fehr and Schmidt and the principal-agent model are combined, and the behavior incentive model is constructed based on the fairness preference. The research shows that, comparing with the complete rationality, when the retailers have a fairness preference, retailers improve the level of efforts, and manufacturers increase the incentive for retailers, so that product sales increase, the incomes of retailers are improved, and the total channel revenue is also improved.