The invention provides a lightning-protection and explosion-proof insulator. The lightning-protection and explosion-proof insulator comprises an upper hardware fitting, a lower hardware fitting, an epoxy barrel and an insulating outer sleeve, wherein the upper hardware fitting and the lower hardware fitting are of a wiring electrode and a grounding electrode respectively; the epoxy barrel is arranged in the insulating outer sleeve; a gap barrel is arranged in the epoxy barrel; a first tapered copper piece and a second tapered copper piece are arranged at the top and bottom of the gap barrel respectively; a nonlinear limiting element is arranged under the second tapered copper piece; the lightning-protection and explosion-proof insulator further comprises pressure releasing holes; at least two symmetrical pressure releasing holes penetrating through the wall of the epoxy barrel are formed in the wall of the epoxy barrel; and sealing parts for backfilling are arranged in the pressure releasing holes.