The invention relates to a chip type high-voltage aluminum electrolytic capacitor, an electrolyte thereof and a preparation method of the electrolyte. The electrolyte comprises the following components of 38.5-77.2% of a main solvent, 10-20% of an auxiliary solvent, 5-25% of a solute, 2.5-5% of an antiseptic, 5-10% of a high-temperature stabilizing agent, 0.2-1% of a hydrogen removal agent and 0.1-0.5% of a hydration-proof agent by weight. The solute is at least one selected from ammonium 2-n-hexyl adipate, ammonium octaned icarboxylate acid, butly octanedioic acid, ammonium 2-n-hexyl adipate oxalate, ammonium sebacate, sebacic acid, ammonium hydrogen azelate, ammonium azelate and ammonium pentaborate. The high-temperature stabilizing agent is at least one selected from polyvinyl alcohol, polyvinyl acetaldehyde, polyvinylpyrrolidone, polyvinyl alcohol succinate and sulfanilic acid. The high temperature resistance is high.