According to the current situation of power system designed a detection device for power harmonic based on Android. Describing the detector hardware implementations and software design methods.The circuit of data acquisition module based on the 16 bit ,6 channels simultaneous sampling chip of ADS8364. Cortex-A9 platform which has equipped with Android operating system can complete configuration management and achieve data processing,data storage,human-computer interaction. Choose add window algorithm to achieve data processing which can reduce the fence effect and spectral leakage problems. Test results show that this detector can extract the harmonic information and meet the testing requirements.