Abstract: A pot experiment with two barley varieties Taixin9425 and Naso Nijo was conducted to study the regulatory effects of 5-azacytidine and sodium butyrate on adventitious root， dry weight， proline and malondialdehyde （MDA）during seeding stage. Waterlogging index analysis showed that Taixin9425 was waterlogging tolerant variety. The waterlogging index of Taixin9425 and Naso Nijo declined by 4.90% and 15.22% after 5-azacytidine treatment. The MDA content in Taixin9425 and Naso Nijo declined by 12.83% and 34.68% after 5-azacytidine treatment. The proline declined in Naso Nijo， while increased in Taixin9425 after 5-azacytidine treatment. The treatment of sodium butyrate had no effect on waterlogging index in both Taixin9425 and Naso Nijo. Compared to the waterlogging， sodium butyrate treatment significantly increased the content of proline and MDA in both Taixin9425 and Naso Nijo. The results indicated that 5-azaC could enhace barley waterlogging tolerance during seeding stage， while sodium butyrate had no effect on regulating the waterlogging tolerance of barley.