Abstract: The weighted correlation measure was used as the grey rice quality index. On the basis of introducing the theory and method of calculation, some primary researches on how the grey rice quality index is applied to evaluating and classifying the rice quality were conducted. The research of comprehensive evaluation of six kinds of rice shows that it is feasible to apply the grey rice quality index to comprehensive evaluation and classification of the rice quality if the index is reasonable and the weighted index is allocated appropriately. The judgment model set up by the subjunctive ideal reference numeral increases the adaptability of the judgment execution.