A reliable islanding detection method is one of the most important function of a well designed inverter based distributed generation (DG) system. Active islanding detection methods have negligible non-detection zone, but they bring some power quality issues to the network. In this paper an islanding detection method which addresses constant current inverter based DGs is introduced. It has both high power quality and low non-detection zone. The method makes a positive feedback between reference current of the constant current controller and the rms voltage of inverter terminal in a way that it could detect islanding in the proper time, while providing constant current appropriately. The efficiency of the method is proved using simulations based on PSCAD/EMTDC.