This paper analyzed current network security of the small and medium-sized enterprise, and discusses the existing problem in small and medium-sized enterprises and the existing technology, and network security and management. Finally the paper points out the network security and proposed network security model with four layers (application layer, system layer, network layer, physical layer) network defense in depth security solutions and network security deployment plan based on the MPDRR (safety management, safety protection, safety inspection, safety, security response recovery).