The paper proposes a UCONF（usage control fuzzy） model based on fuzzy comprehensive control

and gives reference monitors of the model.The model uses fuzzy integrated logic to compute credibility

by which the authorization policy of UCON is simplified.As a result

the rights authorized can be changed dynamically

which may facilitate the granting or revoking of rights.The manageability and excutability of the model can be also enhanced therein.Analysis shows that this model fully reflects trusting relationship between subjects in the open-network environment

resolves the access control issues of combining static and dynamic methods

and ensures the security control of information system.