Most of recent false data filtering mechanisms in WSN added t-MAC (Message Authentication Code) for the data packets, these mechanisms are usually restricted within the t-threshold safe limits, and do not support dynamic routing. Based on the idea of a virtual witnesses cluster, adopting the perturbation-based polynomial technology, this paper proposes a authentication algorithm that made a number of nodes within a cloud cooperate to generate the certification polynomial, adopting the perturbation-based polynomial technology and increasing the difficulty of an attack. On this basis, the proposed false data filtering mechanism can verify the validity of data immediately, and support dynamic routing. Theoretical analysis and simulation experiments show that the new method is not limited by the t-threshold and save as more energy as the transmission jump increasing. Compared with the other mechanisms, the method enhances the anti-trapping ability. It is more suitable for the network with low credibility and the long-distance transmission application.