Abstract: Process mining is helpful for deploying new business processes as well as auditing, analyzing and improving the already enacted ones. I}he namesake task and a repetitive task exist in the business process of system log of a large number. The existing alpha algorithm of the mining algorithm can distinguish them very well. It leads to the results of the process mining will often produce inaccurate flow model. In order to improve the accuracy of the process mining,it put forward an improved method. The new method not only can dig the complex structure,such as circulation structure,free choice structure and so on, but also can dig the eponymous task and repeat task in the log.

Key words: Process mining, Namesake task, Repetitive task, Complex structure