Chinese wall access control (CWAC) is a well known and suitable access control model for secured sharing of commercial consultancy services. It is to avoid the information flow which causes conflict of interest for every individual consultant in these services. The main objective is to model the Chinese wall access control policy using formal concept analysis which extends and restructures the lattice theory. To attain this goal, we develop a formal context in the security aspects of Chinese wall access permissions. We experiment the proposed method in a common commercial consultancy service sharing scenario. The analysis results confirms that the proposed method satisfies the constraints of Chinese wall security policy and its properties such as simple security and -property. © 2014 IEEE.