Abstract: Honeynet deceives the attackers by constructing a trapping environment and masquerading as a real business network. Attracting attackers, monitoring attackers' behavior and analyzing their characteristics have become the trump card of network deception defense. The definition, classification and functions of honeynets were introduced. On this basis, combining the attack protection process of honeynets, the existing research results were analyzed and concluded according to the key technologies of honeynets, such as generation and deployment of deception scenarios, attack trapping, attack behavior analysis, and security enhancement. In addition, the effect and research progress of the above-mentioned key technologies were discussed in detail and the existing problems and shortcomings in the existing honeynet research were summarized. The development trend and challenge in the future were prospected.