The present invention discloses an event log audit method based on a workflow net model. Based on a legal model and historical logs, a brand-new event log audit method is provided to achieve the purpose of auditing event logs according to an analysis method of a programming language. The method can perform determined log audit without backtracking on account of a process model of a block structure. The method comprises the following steps: (1) analyzing problems in the log audit according to the characteristics of the model of the block structure; (2) giving a corresponding appropriate solution for the problems, and then obtaining conditions required by a model capable of performing the determined log audit without backtracking; and (3) giving the audit method. Compared with the prior art, the invention is not limited to a conceptual model, but gives a specific log auditing method on account of the process model of the block structure. The invention provides conditions required by the model capable of performing the determined log audit without backtracking; and a specific auditing algorithm is given, and the model meeting the conditions can efficiently perform the log audit.