Abstract: The influence of different ecological condition on growth and yield of corn variety Zhengdan 21 was studied through sowing-date experiment at Ayang city. The yield, ear row number, and row grain number dropped, the growing process quickened , the maximum leaf area index and dry matter accumulation declined, along with the postponement of summer sowing, The ecological adaptability for high yield of Zhengdan 21 was that whole growing accumulated temperature was 2596.2~2764.5℃ and whole growing daily mean temperature was 23.2~24.0℃, whole growing accumulated sunshine hour was 514.9~603.2h and whole growing daily mean sunshine hour was 4.6~5.3h.