A novel optoelectronic current sensor is proposed to measure direct,alternating and pulse currents.The sensor mainly consists of current-sampling resistor,field-effect transistor(FET),light-emitting diode(LED),plastic optical fiber(POF),and photo-detector.By using the current-sampling resistor and the transfer characteristics of the FET,the current to be measured can be converted into the gate-to-source voltage of the FET and then its drain current,which modulates light intensity of the LED.The current-sensing signal is transmitted to the photo-detector through the POF.By setting a proper direct currrent(DC) bias voltage for the FET,the DC can be proportional to the open circuit voltage of the photo-detector.The DC in the range of 0.03-17.00 A has been measured and its nonlinear error is less than 0.44%.The delay time of the square wave pulse current response is less than 160 ns.Advantages of the proposed sensor include fast response to pulse current,simple and compact configuration,low cost,application in remote and insulating measurement.