Abstract: In order to prevent wheat stem lodging and to fertilize precisely, the experiments on the influence of phosphate and potash fertilizers on mechanical properties of wheat stem were performed with Zhengzhou-wheat 9023 as an object. Mechanical properties (such as flexural strength and flexural rigidity) of second base inter-node were measured by six treatments at five growth stages of wheat, which were jointing stage, booting stage, flowering stage, grain-filling stage and maturity stage. Nonmetallic material testing machine was used in the experiments. Results showed that the influence of potash fertilizer?on flexural strength and flexural rigidity of second base inter-node was significant. The study results provide some references for the research on high yield cultivation and lodging resistance of wheat.