This paper mainly proposes power flow algorithm using OOP(Object-Oriented Programming) in distribution power system. Because the most power system problems are calculated from power flow, it is an important part in power system. Recently, new power generation facilities are steadily installed in the distribution system connected with Microgrid which has been gaining popularity among the industry and utilities. This paper contributes to improve the power flow algorithm using OOP for efficient power flow according to the distribution system configuration fluctuated frequently.