The distributing parameter characteristics of UHV long transmission line lead to the nonlinear relationship between the measured impedance of traditional distance protection and fault distance， which may cause exceeding-to-trip or failure-to-trip problems on distance protection. According to the authors' analysis， the condition for correct action of distance protection is that the error of fault location be no greater than the difference between fault distance and setting distance. It is proposed that the voltage and current at the measuring point be compensated to the terminal of distance section to locate the fault. Simulation results show that this new method can improve the measuring accuracy of the terminal of distance section， which meets the condition for correct action of distance protection， and makes the protection act correctly.