Abstract: Using acid-rich oil as raw materials, the acid value was reduced by esterification with glycerol in the absence of a catalyst. The optimum conditions were obtained as follows: the mole ratio of glycerol to fatty acid was 1.2∶1, the reaction temperature was 240 ℃, and the acid value could be reduced to below 1.66 mg/g for 2 h. The results showed that this process could not only achieve the purpose of fast deacidification within two hours, but also directly produce biodiesel through transesterification. FT-IR analysis confirmed the disappearance of carboxylic acid and the formation of triglyceride. The results of GPC analysis showed that the composition of the oil after deacidification was 21.93% triglyceride, 37.93% diglyceride and 40.14% diglyceride. And the obtained biodiesel was relatively pure fatty acid methyl esters. In addition, the improvement of the process also directly completed the "process roadmap of biodiesel production from oils with different acid values", which had a certain reference value for the development of biodiesel industry.