IN RECENT YEARS, WITH GROWING UP MICROELECTRONIC TECHNOLOGY, THE APPLICATION AND USING OF FPGA IN INDUSTRIES HAS BEEN MORE AND MORE. SO, IN THIS PAPER A NEW STRUCTURE FOR DESIGN AND IMPLEMENTATION OF AN OVER CURRENT RELAY USING FPGA HAS BEEN PROPOSED. THE CIRCUIT CAN COMPUTE THE ANGLE AND AMPLITUDE OF THE ELECTRIC SIGNAL IN VERY LOW TIME AND ESTIMATE IT ACCURATELY IN HARMONIC AND NOISY ENVIRONMENT. IN THIS DESIGN THE FPGA DO THE ARITHMETIC CALCULATIONS WHILE A SINGLE MICROCONTROLLER DO THE OTHER TASKS OF A PROTECTION RELAY. THE REDUCTION OF SIZE AND VOLUME AND INCREASING OF RELIABILITY ARE SOME ADVANTAGES OF THIS DESIGN. FINALLY, THE ACCURACY AND RELIABILITY OF THE PROPOSED CIRCUIT HAS BEEN CONFIRMED BY COMPUTER PROGRAMMING AND SIMULATION.