Breakdown　voltage　of　hybrid　gas-solid　insulation　system　may　greatly　fluctuate　due　to　the　complex　discharge　processes,　and　the　relationship　between　the　breakdown　voltage　and　the　breakdown　path　is　not　clear.　This　paper　studies　the　fluctuation　of　the　breakdown　voltage　and　the　dispersion　of　the　breakdown　path.　The　results　indicate　that　when　the　barrier　is　close　to　the　high-voltage　electrode,　the　breakdown　voltage　fluctuation　is　significant,　and　the　significance　rises　with　the　increase　of　the　barrier　size.　The　breakdown　paths　are　divided　into　two　types,　the　probabilities　of　which　are　related　to　the　barrier　position,　and　the　average　breakdown　voltages　of　the　two　path　types　are　approximate.　Under　50　Hz　alternating　voltage,　residual　charges　have　a　significant　effect　on　the　direction　of　the　breakdown　path　and　have　little　effect　on　the　breakdown　voltage.　The　breakdown　voltage　fluctuates　significantly　when　the　breakdown　path　is　long.　It　is　found　that　the　low　atmospheric　absolute　humidity　is　another　reason　for　the　breakdown　voltage　fluctuation.　©　1994-2012　IEEE.