Cloud computing is getting more and more attention from the data and communication technology industry recently. Almost all the leading organizations of the data area demonstrate their interesting and efforts in cloud computing and discharge services about cloud computing in succession. Be that as it may, if need to make it go further, we should pay more effort on security issues. Particularly, the Internet environment now has become more and more unsecure. With the popularization of computers and intelligent devices, the number of crime on them has increased rapidly in last decades and will be quicker on the cloud computing environment in future. No wall is the wall in the world. We should enhance the cloud computing not only at the aspect of precaution but also in the aspect of dealing with the security events to defend it from criminal activities. In this paper, we propose an approach which using logs model to building a forensic-friendly system. Using this model we can quickly gather information from cloud computing for some kinds of forensic purpose. And this will decrease the complexity of those kinds of forensics.