This article introduces the system architecture of big data security and the idea of realizing active security. In this article, the heterogeneous data fusion problem of big data security is solved by using the method of that converted into text-based form with text description of heterogeneous data structure. The big data mining technology, which is related to the data set, the modeling and algorithm of various intrusion patterns to calculate the probability, mining security risk points, early warning security incident occurred, is discussed. It proposed that big data security is to data acquisition clean up intermediate form of transformation to a text data stream to impact alignment of the security model, weighted arithmetic judged, risk model of the monitoring and intrusion early warning. Looking forward for the future of big data security development of intelligent active security.