Study the change rule of Total Polar Compounds (TPC) of fried oil and evaluate the feasibility of using new indices to characterize the quality of frying oil from the perspectives of the polar compound composition at the regulated discarding point and the correlation between indicators. During the frying process, the TPC generated by oil deterioration will accumulate with the extension of the frying time. At the regulated discarding point, when the TPC is 27%, the frying oil contains 11.2% of oxTGO+oxTGD, which is close to the ratio of TPC and oxTGO+oxTGD stipulated by national standards. When TPC is 27%, the content of oxTGM in frying fat is 3.5%, and the content of oxTGM fluctuated up and down during frying. Pearson correlation analysis showed that there was no significant correlation between oxTGM and TPC with P>0.05, indicating that the application of TPC to evaluate the quality of frying oil actually failed to cover the effective control of oxTGM at the same time. Therefore, two indicators of TPC and oxTGM can be used to evaluate the deterioration of the fat frying process. Considering the potential toxicity of oxTGM is the strongest, the oxTGM value has a certain practical significance as a waste index to characterize the oxidation deterioration of high-temperature frying fat.