The equivalent circuit of a new transformer with additional filtering and power compensating winding was calculated. Firstly, the polygon basic equivalent circuit was analyzed of the transformer with four windings. Secondly, according to the unique designs of the new rectifier transformer, the simplified ray-shaped equivalent circuit was derived. At last, the equivalent circuit model of the new rectifier transformer was built by PSB of Matlab/Simulink, and the correctness of the equivalent circuit was verified by simulation. The ray-shaped equivalent circuit proposed is very simple and clear, which provides an effective method for analysis on its various operating characteristics.