The present invention provides a yeast strain, which is a Saccharomyces cerevisiae strain, is named the AQ yeast strain, and has the preservation number of CGMCC No.7025. The present invention further provides an alcohol fermentation method, which comprises: adopting the yeast strain to carry out alcohol fermentation on an alcohol fermentation raw liquid. The present invention further provides an application of the yeast strain in alcohol fermentation. With the technical scheme, the present invention provides the yeast strain having high activity under the alcohol fermentation condition so as to improve the alcohol content of the mature mash obtained through the high concentration mash alcoholic fermentation method.