Some association technologies were studied. A design model to the computer dynamic forensics system was put forward, and the detail design to the modules was given. According to the features of dynamic forensics, the method of applying data mining and multi-agent into the dynamic forensics, using multi-agent to build the architecture, using data mining technology to analyze the magnanimous data was raised. However, basic mining algorithms cannot be used to analyze digital evidence directly. So, relative improvements of basic algorithms and methods of pattern analysis were put forward, and experiment is performed to prove the feasibility.