A chaotic synchronization method of the optical intercross-injecting and reverse-phase between dual-ring and two rings is presented,based on the nonlinear kinetic characteristic of two lasing fields coupling each other in erbium-doped fiber dual-ring laser. Numerically simulations show that the synchronous systems with two absolute single-mode erbium-doped fiber single-ring lasers and a single-mode erbium-doped fiber dual-ring laser can be chaotic synchronization. Two channels of the chaotic secure communications systems of dual-ring-two-rings are presented and numerically simulated, which mask two sinusoidal frequencies of 0.5 kHz and 10 kHz modulated signals. Their encoding quality is very good and security is robust. They can be well applied in multi-channel chaotic secure communications.