Many research indicate a lot of money and time are spent on maintaining and modifying program delivered.So the policies to support program comprehension are very important.Program comprehension is a crucial and difficult task.Insufficient design, illogical code structure, short documents will enhance the comprehensive difficulty.Developing Web application is usually a process with quick implementation and delivery.In addition, generally a Web application is coded by combining mark language statements with some embedded applets.Such programming mode affects comprehension of Web applications disadvantageously.This paper proposes a method to improving understanding Web by dependence analysis and slice technology.