The paper introduces a upright type high voltage standard capacitor compressed-gas of SF6, which can measure the power frequency voltage of 600kV and 1200kV impulse voltage. The finite element analysis software of ANSOFT was used to simulate the high voltage bushing. The position and size of the grounding shield and the middle potential shield were optimized. While the voltage coefficient k is 41.6% of the middle potential shield, the two peak value of electric field of along the outer surface of busing both are about 0.5kV/mm and the bushing utilization is the best. For electrodes designing, the diameter and the upper and lower arcs of high voltage electrode are determined by the electric field strength. Continuously optimize the size of the shielding electrode, the electric field strength of the surface of the low voltage electrode as possible. Under the lightning impulse withstand voltage of 1440kV, the maximum electric field inside the device shell is 18.1kV/mm. In order to improve the frequency characteristics of the divider, the distance between the low voltage electrode and the inner wall of the shell is only 15mm. According to the size and material of the electrodes, the calculated temperature coefficient of the standard capacitor is 2.05×10-5/K, and Voltage coefficient is 5.5×10-7 with 600kV voltage. The change of capacitance caused by eccentricity is 3.95×10-5, which is the fixed error after electrodes installed.