The invention discloses an X fluorescence determination method of main content SnO2 in a glass refining agent material of stannic oxide, and belongs to a determination method in the field of glass manufacturing. The method sequentially comprises the following steps of using a pelleting press for pressing a standard sample sheet series; putting pressed standard sample sheets onto an X fluorescence spectrophotometer to register the intensity; building a standard curve; verifying the reliability of standard curves by a verification standard sheet with the known ingredient content; detecting the main content of the sample to be detected according to a built standard curve. Compared with a conventional method of complexation and back titration after the alkali fusion treatment, the method provided by the invention has the advantages that the sample treatment process is simpler; no loss exists; automation is realized; the detection efficiency is high; the result is reliable. The standard product of the standard curve is built through the sheet pressing. Compared with a detection method of providing standard products and samples by a platinum yellow crucible fusion method in the prior art, the method has the advantages of safety, energy conservation, uniformity and simplicity; meanwhile, the crucible corrosion is avoided; the data is reliable.