Abstract: To investigate the effect of sowing date on growth and yield of silage maize and to identify optimal sowing date, an experiment was carried out in Hunshandak Sand Land. Two cultivars of maize were sown on May 27, June 4, June 11 and June 18 respectively and their height, leaf area, aboveground phytomass, and phytomass allocation were investigated. The harvest results on 27 August show that the height, leaf area, and aboveground phytomass of the two cultivars decrease with delayed sowing date. Significant differences exist in the above variables for sowing dates between May 27, June 4 and June 11, June 18. Early sowing (from end of May to early June) increases yield of maize for silage over sowing in mid June as commonly practiced by the local people. Phytomass allocation analysis shows that, with delayed sowing date, percent of stem phytomass to total phytomass drops, while the ratio of leaf phytomass to total phytomass increases. As nutritional contents of leaf and stem are different, sowing date can be adjusted by alternation with livestock to realize the full use of silage maize.