针对当前流行的云计算技术,分析了其所面临的安全问题.以BLP(Bell-LaPadula)模型和Biba模型为参考,通过基于行为的访问控制技术来动态调节主体的访问范围,实现BLP模型和Biba模型的有机结合,提出了CCACSM(cloud computing access control security model).该模型不仅能保护云端服务器中数据完整性和保密性,而且使云计算环境具有相当的灵活性和实用性.最后给出了该模型的组成部分、安全公理和实现过程.“,”In view of the current popular cloud computing technology,some security problems were analyzed.Based on BLP(Bell-LaPadula) model and Biba model,using the access control technology based on behavior to dynamic adjusting scope of subject's visit,it put forward the CCACSM(cloud computing access control security model).The model not only guarantees the cloud computing environment information privacy and integrity,and makes cloud computing environment with considerable flexibility and practical.At last,it gives the model's part,safety justice and realization process.