A set of parallel plate vacuum surface flashover experimental platform is adopted to measure the statistical model constants of surface flashover of the common insulating material in the vacuum 45° insulation structure in pulsed power device.The experimental platform uses the Marx-Blumlein high-voltage system to generate high voltage rectangle wave pulse.The voltage is output at full-width at half-maximum of 120 ns

front of 30 ns and 90% flat top of80 ns and the voltage amplitude is within 180～280 kV.The vacuum surface flashover experiment of the insulator sample with thickness within 0.7～0.9 cm and bottom diameter within 7～10 cm is performed in accordance with the test specification preventing occurrence of obvious systematic defect.For obtaining the first breakdown data along the surface

the calculated surface flashover statistical-model constant of cast nylon is 223.1;while

the constants of cross-linked polystyrene and PMMA are greater than 258.1 and 263.9 respectively.There are definite differences between these results and those of other reference

which is worth studying further.