Four different nitrogen fertilizer treatments were set to study the effects of nitrogen reduction on the yield and culm growth characteristics of machine-transplanted hybrid indica rice Yixiangyou 2115 and F You 498, and its relationship with lodging resistance. The results showed that compared with the control （nitrogen fertilizer amount 180 kg/hm²）, with the increase of nitrogen reduction, the yield of the tested rice varieties gradually decreased, but the yield of N150 treatment （nitrogen fertilizer amount 150 kg/hm²） did not decrease significantly, while the yield of N120 treatment （nitrogen fertilizer amount 120 kg/hm²） and N0 treatment （no nitrogen） decreased significantly. The plant height and the height of the center of gravity of the two rice cultivars decreased, the length of the basal internode shortened, and the culm type index of the basal internode increased, while the fullness of the basal internode （dry weight of the basal internode, dry weight of the basal internode per unit length and dry weight of the basal internode per unit volume） first increased and then decreased, the bending moment of the whole plant decreased, the bending moment at the breaking increased, which resulted in a decrease in the lodging index and strong lodging resistant. Correlation analysis showed that lodging index was positively correlated with grain yield, plant height, the height of the center of gravity, bending moment of the whole plant and the length of the basal internode; and was negatively correlated with the internode diameter, bending moment at the breaking, culm wall thickness, culm type index and fullness of the basal internode. In summary, suitable nitrogen reduction （N150） could simultaneously achieve nitrogen reduction and stable yield and high lodging resistance of machine-transplanted hybrid indica rice. However, excessive nitrogen reduction （N120 or N0） could greatly improve lodging resistance, it was difficult to achieve high or stable yield.