Distribution system buses optimization can improve the power flow calculating efficiency and enhance real-time ability of control system.This paper is established in the demand of automatic voltage control system of region distribution system and the characteristic of network structure

proposed a new buses optimization method called as eliminating one method based on star-delta transform.Using the new method

because the branch linked with the eliminated bus is one there will not bring new injected element

the star-delta transform can assure the branch is only one for any bus.This method can achieve perfect optimization purpose and at the same time with the strongpoint of calculating load less

writing programmer simple and with receivable practicability.