Compared with the other dry-type transformer, the cast resin transformer has many advantages. But in consideration of economy, developments in the voltage level and capacity are restricted. In this paper, the authors carry out simulation verificaion on a novel insulation structure of 110kV cast resin transformer which is still in design.Firstly, 2-D model of the transformer is built up. Secondly, electric field of this model is simulated with FEM in different link positions.Thirdly, the electric field in the air insulation and epoxy insulation is analyzed. Final, the conclusion that the insulation structure could meet the demand of power-frequency voltage-withstand test is proposed according to the analysis and the following research to do is forecasted.