Abstract: From the non-detection zone and the current harmonic distortion, which are two effectiveness indexes of islanding detection, according to the relationship between the parameters of islanding detection algorithm and the non-detection zone and harmonic distortion, a new algorithm based on parameter adaptive is proposed to improve the active frequency drift (AFD) and the Sandia frequency shift (SFS) algorithm. It can select more appropriate parameter, when the load changes. And it proved that in the improved algorithm, the success rate of islanding detection became higher, and the harmonic distortion became smaller by simulation.