Phase sequence is the order in which the rotated voltage or current generation by three-phase system attain peak or maximum value. Each sequence voltage is 120 degree apart. Therefore, the maximum value which is achieved by each sequence is at the definite time interval. Based on this individual response time a new technique of phase detection system as discussed an algorithm is developed in order to detect phase sequence. A microcontroller is used to incorporate the algorithm into it. The simulation result is illustrated here to verify the proposed algorithm. A prototype device is built to compare the practical and simulated result.