Seven cultivars of rapeseed and treatments of different temperature controlled by illumination incubator(GDN) were used to study the seed germination and seedling development of rapeseed.The results showed that the germination and emergence process of the cultivars was basically the same under the control condition.There was no obvious difference between them.With the decrease of temperature,the process of germination and seedling of all cultivars became slow compared with the control.Shengguang 77,Deyou No.8 and Fengyou 730 were more sensitive to low temperature.With the decrease of temperature,germination index(GI) and seedling vigor index(SVI) decreased significantly with the decrease of 29.5%-99.5% and 8.7%-97.5%,respectively.Mean time of germination prolonged significantly when the temperature decreased.The seeds under 15℃/10℃ and 10℃/5℃ extended by 0.5-4.0 d and 4.6-12.0 d,respectively.Root length,total length decreased when temperature decreased.Among them,Fengyou 823 was less affected by low temperature while Shengguang 77 and Deyou No.8 were more sensitive to low temperature.Under 10℃/5℃,the root to shoot length ratio reduced 15.1%-47.5%.The dry weight per plant of all cultivars increased under 10℃/5℃,except Shengguang 77,whose fresh weight per plant reduced significantly.The reduction of its rate of total dry weight/total fresh weight reached 26.0%-48.9%.