Abstract: The effects of different treatments of winter wheat residues including returning straw(RS) , high stubble(20 cm high) with mulching(HS) and zero stubble(ZS) on eco-physiological responses of mechanized sowing summer maize(Zea mays. L.) in North China were explored to seek the best treatment of winter wheat residues in 2005 and 2006 by field testing.The results showed as follows: in the prophase growth of summer maize, RS was not only propitious to increase soil moisture content and demand for water of summer maize growth, but also balance and improve the status of soil temperature through the function of heat preservation on lower soil temperature condition and decrease the temperature at higher soil temperature. It could increase the ability of water storing and preserving as well. At the period of three full expansion leaves, the total area of leaves and dry weight of each plant by the treatment of ZS was the best. At the period of six full expansion leaves these characteristics and photosynthesis traits by the treatment of RS were the best, and its yield was the highest. So RS has a larger extension value for providing better ecological conditions for mechanized sowing summer maize and promoting the growth and development and increasing the yield of summer maize.