Analysis of cluster behaviors of the on-coming cluster is an essential measure for high value locations on the battlefield. Unlike target tracking and clustering analysis, cluster behaviors analysis under cluster security requirements remains an open issue, which is a joint analysis of clustering, intent reasoning and activity regions. To address this issue, a framework for cluster behaviors analysis is proposed by incorporating expert knowledge and domain knowledge, and a knowledge-assisted score function with is designed to improve the accuracy of intent reasoning network, overcoming the effects of possible knowledge errors. The framework consists of three modules for cluster analysis, intent reasoning and activity region analysis for typical tasks, in which an intent reasoning network is constructed to obtain cluster intents by using a hybrid knowledge and data driven approach. Furthermore, considering the complexity of the battlefield environment, different tasks and corresponding activity region optimization functions are designed for cluster activity region analysis, which are vital elements of cluster behaviors analysis. Simulations demonstrate the effectiveness of the proposed cluster behaviors analysis framework.