Good security is indispensable to any quantum secret communication protocol. However, information leakage has been a great security threat to quantum dialogue. In order to solve the problem, a quantum dialogue protocol without information leakage via cavity QED was proposed, which made full use of the evolution law of atoms in cavity QED. The proposed quantum dialogue protocol avoided the information leakage problem by using the measurement correlation property after entanglement swapping between two Bell states via cavity QED, and could securely exchange 4 bits secret messages per round communication. The results show that the proposed protocol is able to detect the active attacks from the outside eavesdropper through security checking, such as the intercept-resend attack, the measurement-resend attack and the entanglement-and-measurement attack. Therefore, it has good security towards both the information leakage problem and the active attacks from the outside eavesdropper.