The invention discloses a process method for deacidifying high acid thickened oil, wherein the viscosity of raw oil is firstly measured in 40 DEG C, the process method for deacidifying the high acid thickened oil uses following steps when the viscosity of the raw oil is less than or equal to 30mm2 s-1, but the raw oil is preheated to a viscosity which is less than or equal to 30mm2 s-1 when the viscosity of the raw oil is bigger than 30mm2 s-1, then the process method for deacidifying the high acid thickened oil uses the following steps: the raw oil and a deacidification agent are stirred or vibrated in a closed condition until a solvent phase and an oil phase completely reacts, are stood until a mixed agent oil system is divided into an upper and a lower layers, the upper layer is the solvent phase, the lower layer is the oil phase, then the oil phase on the lower layer is extracted, solvent which is mixed in the oil phase can be distilled in normal pressure, the deacidification agent is a mixed solution of ammonia water and ethanol, the quality radio of the raw oil and the deacidification agent is 1: 0.75-1.5, and the quality radio of the ammonia water and the ethanol is 3:97-2:23 in the deacidification agent. The process method for deacidifying the high acid thickened oil is simple in technological process and mild in operating conditions, does not have an emulsion after the solvent phase and the oil phase are mixed, and is rapid in layering speed and obvious in deacidification effect.