Based on wheat plant alteration,we observed and analysised winter wheat planted in spring and spring wheat introduced in Yuxi area.The results indicated that:Yumai 18 had lower yiede that planted before middle February or those sprouts had just come up in the first ten days of March.spring wheat yiede were higher than winter wheat,s sowing at the same time ,but we should choice the wheat varieties ,are matured early ,grain-filling quickly and resistanted to high temperature in laster period,ang paid attention to sowing in time and increasing grain weight per spike.