Abstract: There is no appropriate internal isolation mechanism for important production information system based on cloud computing. Here the main access control technologies were compared thoroughly and then two-layer key management scheme was put forward. In terms of the first layer, access control polynomial based on one-way hash function was constructed to achieve the separation of information flow between subgroups, that is, the information isolation within any department of a company was accomplished. Based on the first layer, a hierarchical key management was presented for different subgroups so as to realize the access control between different departments of a company. Then the security and complexity were analyzed. Finally, through the example and simulation experiment, the access control model based on two-layer key management scheme was verified.