Nowadays, a new security problem is arising in intranets. The threats from inside an organization account for a rapidly increasing proportion of losses. A new concept of "File View" is proposed to resolve this security problem in intranets, which uses the structure of database view for reference. Because of the differences between file system and database, there are some challenges in extending this proposal to file systems. This paper proposes an algorithm to protect confidential information in file system from being accessed by illegal users. First, the paper proposes an algorithm as "File View Access Control Algorithm"(FVACA) which revises the algorithms proposed in previous work. Then, to verify the feasible of this algorithm, this paper suggests to realize it on "Microsoft Office Word" which is one of the most popular digital formats used in intranets. For protecting the confidential information in file view, a method based on the compound format of "MS Word" is adopted. Finally, the experiment based on "MS Word" shows that FVACA is effective on protecting content from being accessed by illegal users.