The high quality of new tetraploid grape cultivars ‘Jumei’ was the hybrid of ‘Kyoho’ grape and ‘Muscat hamburg’ grape,which with high resistant diseases,high yield and growth vigorous of branch.It is popularly welcomed by consumers for the high sugar content and good taste of its fruit.But in the cultivation practice，downy mildew occurs frequently.The quality of the fruit was influented.The research group strengthened the investigation and study on the occurrence regularity of the grape downy mildew and found a scientific and effective method controlling the disease.