In order to solve the problem of fault direction identification in a smart distribution network with distributed generators（DG），a method for identifying fault direction by comparing the amplitude of voltage variation is proposed.According to the distribution characteristic of voltage variation in different fault regions，this direction element can determine the fault direction by comparing the relationship of amplitude between bus voltage variation and defined operation voltage variation.In consideration of the feature that the equivalent system impedance，line impedance and load impedance may vary within a wide range，a great deal of studies has been conducted to establish the setting rule of amplitude and angle of the setting impedance.According to different impedance characteristics，different types of criteria are used to coordinate the work，so as to improve the reliability of fault directional elements.Finally，case simulation by DIgSILENT has proved the feasibility and reliability of fault direction identification criteria based on amplitude comparison of voltage variation.