LDAP is a set of protocols for accessing information directories which provides data integrity and authentication. It takes attacks on clients, Internet and benign attacks on servers into account. But the malicious attacks on servers and software errors is rarely involved. In this paper, a secure aware Byzantine fault tolerant LDAP system is proposed, which can tolerate malicious faults occurred in the servers. By using a new Byzantienfault- tolerant algorithm, the proposed LDAP system guarantees safety and liveness properties assuming no more than f replicas are faulty while it consists of 3f +1 tightly coupled servers. For the series of optimization, the system not only provides a much higher degree of security and reliability but also is practical.