In view of the inability of the existing variable-step least mean square（LMS）harmonic current detection to eliminate the interference of the common frequency harmonic current and fundamental reactive current with step update plus the poor tracking ability of the jump system，a variable-step LMS harmonic current detection algorithm based on the versiera function is proposed.The algorithm eliminates the interference of the fundamental reactive current and harmonic current using the time mean estimate of the instantaneous cross-correlation between the reference input signal and the error signal at the moment which is obtained by subtracting the filter output from the load current.The modified versiera function is used to adjust the algorithm step，thereby ensuring that the dynamic response time is not increased.This method has not only a smaller steady state error，a better tracking ability of the jump system，but also its parameter value is less dependent on the size of the load current.Computer simulation results demonstrate the validity of the proposed method.