Abstract: After deep-frying, peanuts have a richer flavor and taste, but polar substances will be produced during frying process．Using soybean oil as frying oil, a method for detecting polar compounds content of oils and fats in fried peanuts was studied．Acid value, peroxide value and polar compounds content of soybean oil before and after frying were determined, and conductivity method was used for rapid detection and correlation studies between various indicators．Results showed that petroleum ether could be used as a solvent for oil extraction from fried peanuts to detect polar components content．During deep-frying, polar components content of oils and fats in fried peanuts increased with an increase of frying oil polar compounds content, however, it was lower than frying oil polar compounds content in the same period．Acid value, peroxide value, and conductivity of frying oil showed an overall upward trend with an increase in polar compounds content, three indicators could be used as an online monitoring basis for replacement of vegetable oil during frying process．There was no significant linear relationship between polar compounds content and conductivity value, and application of conductivity method to rapid detection of polar compounds content in frying oil needs further study．