Abstract: According to the characteristics of optical fiber self-cure ring networks,a synthesis synchronization method for line differential protections is proposed.The method uses the results of ping-pong method as the primary criterion and results of reference phasor method as the auxiliary criterion.The method proposed can implement self-adaptively data synchronization with the auxiliary criterion to distinguish the working state of self-cure ring network.When the reference phasor method is used to synchronize data,the distance blocking logic is added to improve the reliability of protection.Testing results of real-time data simulator（RTDS） show that the method is easy to operate and has reliable performance.