Abstract: In this paper, the construction and implementation of a role based access control （RBAC） model are discussed, which are two hot topics in the research of role based access control. A new RBAC model which is named “NRBAC model” is presented. Besides comprehension, this model has advantages of being close to the real world and having a consistent form over RBAC96 models. For the implementation of NRBAC model, a new implement mechanism, which is a binary two key lock pair access control scheme using prime factorization （TPB 2 KLP）, is presented. This mechanism overcomes the disadvantages of the implement mechanism of RBAC which have already been presented, and it has both the advantage of the small number of lock vector updating and the advantage of low possibility of overflow.