Aluminum (Al) toxicity is a serious agricultural problem in acid soils which account for about 40% of the worlds arable land. Tolerance study on the Al toxicity in some resistant plants is helpful to find an economic and sustainable approach for improving crop production on acid soils. In this research, two buckwheat (Fagopyrum esculentum Moench) varieties (Xiaobaihua and Xiqiao No.5) seeds were soaked in Al solutions (0, 10, 100, 1000 and 5000 mg•L-1 Al3+) for 5 hours to investigate the effect of Al on seeds germination and seedling growth. 
The result indicate 10 and 100 mg•L-1 Al3+ soaking can decrease the seeds membrane permeability by 6.2%、34.3% in Xiaobaihua and 54.7%、44.6% in Xiqiao No.5. Accordingly, less main nutrition substance accumulated in seeds was leaked. Al (10～5000 mg•L-1Al3+) soaking can not significantly change the germination percentage of two varieties, but 5000 mg•L-1 Al3+ can restrain the germination index and the vigor index by 3.2% and 23.2% in Xiaobaihua, 46.3% and 41.6% in Xiqiao No.5. After seed germination, Al inhibited the root elongation by 7.0%～50.1% in Xiaobaihua, 12.1%～39.6% in Xiqiao No.5. On the seventh days after germination, 10、100、1000 mg•L^-1 Al³⁺ had no significant effects on the malonaldehyde (MDA) content in buckwheat leaves of two varieties compared with the control. However 5000 mg•L-1 Al³⁺ increased the MDA content by 19.1% and 9.6% in Xiaobaihua and Xiqiao No.5 respectively. 5000 mg•L-1 Al³⁺ also promoted the activity of peroxidase (POD) by 53.4% in Xiaobaihua leaves and 11.6% in Xiqiao No.5. Lower concentrations of Al can decrease the content of soluble sugar (SS) and proline (Pro) in the leaves of two varieties. Higher concentrations, especially 5000 mg•L-1 Al³⁺, can increase the content of SS and Pro by 42% and 18.1% in Xiaobaihua, 68.1% and 12.6% in Xiqiao No.5. The reaction of catalase (CAT) to Al in two varieties was different. The CAT activity in leaves of Xiaobaihua was more sensitive to Al than that in Xiqiao No.5. The testing dates showed that buckwheat seeds and seedlings had high resistance to Al, and lower concentrations of Al could promote germination of buckwheat seeds by decreasing the membrane permeability. The promotion of POD activity and the increasing of SS and Pro contents in two varieties leaves played an important part under Al stress. And different buckwheat varieties had different reaction to Al.