The current print service is faced with many security challenges, such as network attack and data leakage, and its security level completely depends on the information security of the external environment. As such, a secure printing architecture based on private cloud and intelligent defense is introduced in this paper. The architecture with private cloud as the core provides a unified and transparent access interface for print service by virtual printing. It monitors and manages the printing business flow on the basis of authentication and printing security policies. Meanwhile, it securely isolates the printing output device from the client network and the data center network with an access control mechanism for the end point, realizing the on-demand access to print service and intelligent defense against network exceptions. The Jmeter-based stress testing and the hping3-based security testing demonstrate that the system with this architecture has good user experience and strong robustness. To be specific, it spends less than 2 s successfully handling 100 consecutive requests from 400 concurrent clients respectively for submitting and outputting print jobs when it is not attacked, and the exception rate of outputting print jobs for the same requests is only 3.62% when the system is attacked by 5000 SYN packets/s.