Two different varieties Xianyu 335 and Zhengdan 958 were used as the test materials and five potassium fertilizer levels were applied to study the effects of different potassium level on the morphology，dry matter，stalk strength and yield of maize.The results showed that the ear height coefficient showed a V shaped curve with the increasing of potassium fertilizer application rate and reached the lowest value at K2 treatment.To the Zhengdan 958，there was no significant influence of potassium fertilizer application rate on the length and the ratio of the length to diameter of internode，while those of Xianyu 335 were increased firstly and then decreased and increased again in the end with the increasing of potassium fertilizer rate.The ratio of dry matter，the dry weight and stalk strength between different internodes were increased firstly and then decreased with the increase of potassium fertilizer rate.The correlation analyses showed that strength of internodes was positive significantly correlated with the dry weight of internode.The moderate potassium fertilizer application had positive influence on the yield of maize.In this study，the yield of maize was the highest when the potassium fertilize application rate was 100 kg/hm2.