Based on the operation experience, the analyses of the electric field distribution in lower part of the bushing and the design method used in condenser body, it is found that for HV transformer bushings the flashover voltage in oil and the partial discharge inception voltage(PD1V) are usually lower.Two measures are suggested for improving the properties, namely, a new kind of design method and the optimized shapes are used. The measures are successful verified by partial discharge(PD) measurements and flashover tests carried out on the real bushings.