A fatty acid value determination method in grain was developed by using automatic photometric titrator with KOH as standard titration solution in this paper, in which magnetic stirring apparatus was selected as extraction device, anhydrous ethanol was used as extraction solvent, and thymol blue was used to control directing terminal. Finally, the fatty acid value was calculated by combining the consumed volume of KOH's standard titration solution. The instrument can automatically complete the whole process of extraction, filtration, quantitative transfer, titration and calculation. The results showed that the determination method has high precision, and the repeatability, accuracy and stability can meet the requirements of the national standard method, the consistency between instruments can meet the repeatability requirement of national standard method, the measuring time of paddy and wheat flour were one-third and one-half respectively of those by potentiometric or manual titration, and the measuring time of maize was two-fifths of the potentiometric titration and one-half of the manual titration. With a wide application range, the method was easy to operateand less to be disturbed by human factors, it is very suitable for batch and rapid determination of fatty acid value in grain. In a word, this method provided a suitable method for strict quality control in the grass-roots grain storage companies when purchasing grain and detection of large quantities fatty acid value in grain inspection agency.