From 1993 to 1994,according to the basic principles of culture,prevention and control and meteorology,a series of experiments were conducted on comparison between the two ways of the sparse transplant of the drily raised rice seedlings and the conventional rice culture in terms of field microclimate,mildew occurrence and its prevention and control. The results show that if rice seedlings are drily raised and sparsely transplanted,the field microclimate is raised and the moist t ure is lowered with more sunlight between the rows. As a result,the mildew occurrence periodcan be delayed and the mildew degree can be lessened with less farrn chemical,lower agricalturalcost and higher output.