Abstract: When Beer malt was infected with fungi, it would lead to premature yeast flocculation. So it is important to study the relationship between fungi and the phenomenon of Premature Yeast Flocculation (PYF) . Eight kinds of fungi were selected from PYF+malt. In order to learn about the relationship between fungi and PYF, eight kinds of fungi were inoculated into the media which prepared by malt shell and distilled water, separately, and then produced wort agreement with non-shell malt and followed on boiling, filtering, pitching yeast and testing the value of Premature Yeast Flocculation. According to the consequences about the relationship between barley fungi and Premature Yeast Flocculation, conclusions could be drawn that both rhizopus oryzae and Aspergillus flavus could apparently and heavily bring about Premature Yeast Flocculation. And Fusarium could also apparently bring about Premature Yeast Flocculation, but weaker than rhizopus oryzae and Aspergillus flavus. Geotrichum candidum and Alternaria tenuissima tend to normal fermentation. What’s more, Aspergillus niger and cladosporium tenuissimum lightly result in Premature Yeast Flocculation. Penicillium lead to sporadic flocculation. It might be connected with strains quantity and enzyme activity. It is necessary to deeply study.