The wind resistance of rapeseed stem was studied to provide a theoretical basis and technical support for lodging resistance cultivation and lodging prediction. Two varieties of HZ 62 and JZ 158 were selected, and the single factor experiments at three levels of planting density (30 × 10⁴, 45 × 10⁴ and 60 × 10⁴ plants·hm^-2), nitrogen application rate ( 120, 240 and 360 kg·hm^-2 ) and sowing time ( Sep. 20, Oct. 1 and Oct. 10 ) were set up. The mechanical indexes of stem vibration, wind vibration and bending characteristics at flowering stage (early flowering, full flowering and end flowering) and lodging index 20 days after end flowering were measured. The results showed that by increasing the planting density, the natural vibration frequency, damping ratio, wind vibration frequency, elastic modulus and bending stress of rapeseed stem at flowering stage increased first and then decreased, the maximum amplitude and lodging index decreased first and then increased, and the lodging resistance increased first and then decreased. The natural vibration frequency, damping ratio, wind vibration frequency, elastic modulus and bending stress of rapeseed stem decreased, the maximum amplitude and lodging index increased, and the lodging resistance decreased by increase of nitrogen application rate. The natural vibration frequency, damping ratio and wind vibration frequency of rapeseed stem at flowering stage increased gradually, the elastic modulus, maximum amplitude of bending stress and lodging index decreased gradually, and the lodging resistance increased gradually by delay of sowing date, t. The BP neural network model for predicting lodging index of HZ 62 and JZ 158 was established.