Abstract: In order to promote the breeding of new mid-and late-maturing maize varieties in Heilongjiang Province,this article reviewed and summarized the hybrid improvement of Dan 705 and Huangzaosi by Qiqihar Branch of Heilongjiang Academy of Agricultural Sciences,integrating the excellent characteristics of Lyudahonggu Germplasm and Huangzaosi.The process of screening out 7 new germplasm resources and further breeding new maize variety Nendan 23 and excellent lines.