In order to investigate the influence of Monascus purpureus and Saccharomyces cerevisiae co-fermentation on the flavor of sweet red yeast rice wine， the two different strains in various proportions were combined and used for rice wine fermentation. The dynamic changes of microorganisms， organic acids and volatile aroma components were monitored during fermentation， aiming to reveal the causal relation between microbial fermentation and flavor compounds production. Microbial count showed that yeast increased in the early 12 h and then began to decrease， and Monascus correspondingly decreased in the beginning and then increased gradually during fermentation. But addition of Monascus obviously promoted yeast proliferation. Moreover， the alcohol content increased slowly as sugars were consumed during fermentation， and more organic acids were produced after 36 h of fermentation， which were mainly composed of lactic acid， acetic acid， citric acid， and tartaric acid. Remarkably， higher inoculum size of Monascus used in fermentation resulted in more sugar consumption and more alcohol and organic acids production in rice wine. Furthermore， 47 volatile components in total were detected during fermentation， including 6 alcohols， 14 acids， 12 esters， 8 ethers， 4 aldoketones， 2 quinones， and 1 phenol， in which higher alcohols （2-phenylethanol， vanillyl alcohol， isobutanol） and esters accounted for the highest content. The relative contents of acids decrease constantly， while the relative contents of alcohols， esters， and ethers increased during fermentation. Besides， addition of Monascus prominently led to a rapid increase in esters production in early fermentation and a final higher concentration of esters. To sum up， addition of Monascus in rice wine fermentation promoted the proliferation of yeast and the generation and enrichment of diverse organic acids and volatile components， especially the esters. Co-fermentation of M. purpureus and S. cerevisiae significantly contributed to the abundant flavor compounds in sweet red yeast rice wine.