Since the traditional traveling-wave differential protection cannot be applied to Teed transmission lines， this paper presents a novel traveling-wave differential current expression. The characteristics of differential current at the internal fault state are studied. The restraint traveling-wave is introduced to avoid transient unbalance of differential current under all kinds of operation conditions. Accordingly this paper describes a new scheme with little percentage-ratio restraint characteristic based on traveling-wave differential protection. It also retains high sensitivity for internal high-resistance fault. Theoretical analysis and EMTP simulation show that the scheme operates sensitively and rapidly. Besides， it is realizable and applicable using currently available technique， for it has no special demands on the sampling rate and transmission speed.