At present, most enterprises adopt laboratory testing methods such as sampling, sample delivery, testing, feedback, and adjustment to inspect oil quality. Because this method mainly depends on the human eyes and work experience of operators, the detection error is large, the detection cycle is long, and the detection means obviously lags behind the technological requirements. In this paper, a new detection method is proposed, which combines digital image processing technology with traditional chemical detection methods to realize the automatic detection of oil acid value in oil processing. Moreover, it changes the previous laboratory intermittent inspection method of product quality into online continuous inspection and control, reduces errors caused by various interferences, and improves the accuracy and reliability of oil acid value detection. By measuring the acid value of oil, it can evaluate the edible quality of oil, provide the calculation basis for the amount of alkali needed for oil refining, and judge the quality change of oil during storage, so the detection of acid value of oil has great practical significance.