The invention discloses a method and device for compensating harmonic current and voltage unbalance. The method used for compensating the sub-harmonic current in a wind power station comprises the steps that harmonic current data I[k-all]/I[all] on an exit of the wind power station are obtained and sub-harmonic current data I[k-n]/I[n] of each wind generating set are obtained; each sub-harmonic current data compensation amount THDK-Setpoint of each wind generating set is calculated based on the obtained harmonic current data; according to the calculated value of each sub-harmonic current data compensation amount THDK-Setpoint of each wind generating set and the distribution condition of each sub-harmonic current data I[k-n]/I[n] of the corresponding wind generating set, harmonic current compensation distribution judgment is conducted; according to the result of the harmonic current compensation distribution judgment, self-adaptive harmonic compensation is selectively conducted on each wind generating set by means of each calculated sub-harmonic current data compensation amount THDK-Setpoint of the corresponding wind generating set.