Based on the NCEP/NCAR 1951—2004 midsummer(July—August)data, the relation to the wind field and the contemporaneous temperature and rainfall fields at 160 China stations is studied by analysing the EOF main models of these factor fields. This paper indicates that the first EOF main model of wind field over East Asia has close relation to the China temperature and rainfall fields in the midsummer at the same term, and the main models of the three factor fields are closely related.The abnormal character of large scale wind field at 500 hPa has been explored when the low temperature and flood happened in midsummer.The results indicate that the variance of the precipitation and temperature explained by wind filed at 500 hPa is obviously greater than that by geopotential height filed at 500 hPa.