Abstract: The loss law of oryzanol and its four main feruloyl esters in alkaline methanol system were studied in the present study. The four main components of oryzanol were analyzed by high performance liquid chromatography with methanol/acetonitrile = 1/1 (V/V) as mobile phase. The four components were cycloartenyl ferulate (CAFA), 24-methylenecycloartanyl ferulate (24-MCAFA), campesteryl ferulate (CampFA), and β -sitosteryl ferulate (SitoFA). The standard curves of the four main components were firstly established. The standard curve equations of CAFA, 24-MCAFA, CampFA, and SitoFA were y = 34889x-63757, y = 34813x-112228, y = 36565x-67528, and y = 35601x-32177, respectively. The R² of the standard curve regression equations of four main components were 0.9995, 0.9994, 0.9990, and 0.9986, respectively. Oryzanol was dissolved in alkaline methanol with pH value ranging from 7 to 12, and oryzanol and its four main components were quantitatively detected at different reaction times to investigate the loss law of oryzanol in alkaline methanol system. It was found that the loss of oryzanol increased linearly with the extension of heating reflux time under the same pH value. When the pH values were 7, 8, 9, 10, 11, and 12, the loss rates of oryzanol in 1-12 h were 7.41% -29.54%, 4.04% -33.66%, 11.08% -38.10%, 10.86% -38.61%, 12.62% -45.45%, and 22.36%-48.01%, respectively. The loss of oryzanol increased with the increase of pH value at the same heating reflux time. When the pH value was gradually increased from 7 to 12, the loss rate of oryzanol changed in the range of 7.41%-22.36% with 1 h heated reflux time, and it was changed in the range of 29.54% -48.01% with 12 h heated reflux time. Under the same heating refluxing time, the losses of CAFA and 24-MCAFA increased slowly with the increase of pH value, while the losses of CampFA and SitoFA increased rapidly. The loss degree of the four feruloyl esters was in this order: SitoFA>CampFA>24-MCAFA>CAFA, and these differences gradually increased with the increase of pH value. The maximum loss rate of SitoFA was approximately 3 times that of CAFA and 24 -MCAFA, while that of CampFA was approximately 2 times that of CAFA and 24-MCAFA. This study is expected to provide a theoretical basis for the extraction of oryzanol from rice bran oil and the application in food, medicine, cosmetics and other fields.