The asbestos rubber fiber gaskets and epoxy gaskets were soaked in the seawater， alkaline solution（ 10 % NaOH ）， acid solution（10 % H2SO4） and heavy oil， and the variation of the volume resistivity and surface resistivity of the gaskets with soaking time were studied. The results showed that the wet resistivity of the asbestos rubber fiber gaskets reduced to 102 Ω（ or Ω?cm）level when being soaked in the alkaline solution and acid solution for two months and the period of validity of the insulation was inferred to four months in seawater， and however， the wet resistivity of the epoxy gaskets could remain 104~6 Ω（or Ω?cm） level， and as the conclusion， the performance of the insulation of the epoxy gaskets is much better than that of asbestos rubber fiber gaskets.