A current control method and system for a voltage asymmetry fault is disclosed. When a voltage asymmetry fault occurs, a first current limit value is obtained based on a post-fault positive-sequence voltage and a pre-fault positive-sequence reactive current, and a second current limit value is obtained based on a post-fault negative-sequence voltage and a pre-fault negative-sequence voltage. A third current limit value and a fourth current limit value are obtained based on the first current limit value and the second current limit value. A magnitude of a positive-sequence reactive current is limited by using the third current limit value, and a magnitude of a negative-sequence reactive current is limited by using the fourth current limit value.