Abstract: In order to clarify the effects of sowing date and diammonium phosphate application rate on lodging resistance, growth and development, yield and quality of qingke in alpine region. The test was conducted using Kunlun 14 and Menyuanlianglan as materials. In 2020, three sowing dates were set up on March 15 (early sown S1), March 31 (conventional S2) and April 16 (late sown S3), and the lodging characteristics, growth and development characteristics and main nutrients in the grains of qingke were analyzed. In 2021 and 2022, five diammonium phosphate levels: 150, 225, 300, 375 and 450 kg·hm^-2 (expressed as E1, E2, E3, E4 and E5, respectively) were set on the basis of high yield and suitable sowing date, and the agronomic traits, grain and straw yield, grain nutrient composition and straw feed characteristics at maturity were determined. The results showed that: 1) The delay of sowing date facilitates the accumulation of lignin monomers G (guaiacyl), S (syringyl), and total lignin content in stems, increased stem weight and stem strength, and enhanced the lodging resistance of stems; However, it inhibited panicle and grain development (decreased spikelet number, grain number per spike and 1000-grain weight), and reduced grain yield mainly by inhibiting 1000-grain weight. It also promotes the accumulation of crude protein in grains and reduces starch content. 2) Appropriate amount of diammonium phosphate increased the wall thickness, stem thickness, stem weight and stem strength of qingke, promoted the lateral growth and development of stems, improved the lodging resistance of stems, and increased straw yield. At the same time, it promoted the development of roots and ears, which was conducive to the increase of spikelet number and grain number per panicle, and the grain yield was significantly increased, and the grain and straw yield was the highest under E3 treatment. Contribute to the accumulation of starch content in the grain; At the same time, the contents of straw hemicellulose, neutral detergent fiber and acid detergent fiber were reduced, and the crude protein content and relative feed value of straw were increased. In conclusion, the cultivation mode of early sowing at the appropriate time and moderate reduction (conventional reduction of 25.00%~33.33%) could promote the growth and development of qingke plants, help to improve the nutritional value of grains and the quality of straw feed, and was an effective cultivation measure to improve the yield and quality of qingke grains and straws.