Abstract. With the rapid development of network technologies and deteriorating of network environment, traditional single-net security system can't satisfy the security requirement. Excellent security performance of biological systems impels bio-inspired network security theory to be a hot topic currently. We advance Bio-inspired Multi-Net Security (B-MNS) system which implements the functional distributary of different subnets by state transition in Multi-Net Paralleling (MNP) mechanism. Firstly, concept model of B-MNS and MNP mechanism are outlined; secondly, parameter estimation and modifying algorithms are introduced to construct the mathematical model of B-MNS; at last, the practicability and high efficiency are proved by a simulation.