Misoperation of the differential protection of generator may happen during transient state of the sympathetic inrush. After theoretic study and practical data analysis， it is found that the phase difference of currents at two terminals of the generator is large and the second harmonic component is also large， but the restraint current is small when the sympathetic inrush occurs. So the protection operates falsely in non-restraint area. This paper presents a new method for differential protection with enhanced restraint function. Its acting characteristic consists of two section lines. Taking the restraint current inflexion point as a separated boundary the area is divided into two part. At the upper part the percentage restraint characteristic is still adoptable. At the lower part， both the ratio of second harmonic to the fundamental component and the relationship of the differential and the restraint current are applied to implement the enhanced restraint function. The test results verify its validity and reliability.