Abstract: So far there is little information available about biochar effects on saline-sodic soil.To evaluate the efficiency of biochar on saline-sodic soil,we conducted an incubation experiment by mixing different ratios of biochar and hydrochloric acid added to saline-sodic soil to study the effects of biochar on soil pH,electricity conductivity,soil bulk density,hydraulic conductivity,height and dry weight of oat.Results showed that 2% biochar with 30 mL·kg^-1 of 0.5 N hydrochloric acid,reduced light saline-sodic soil pH to 7.61,decreased bulk density by 19.2%,while hydraulic conductivity,plant height and dry weight was increased by 31.6%,6.3% and 65.5%,respectively,which could be used to improve mild saline-sodic soil.5% of biochar with 10 mL·kg^-1 0.5 N hydrochloric acid reduced moderate saline-sodic soil pH to 8.06,decreased bulk density by 19%,while hydraulic conductivity was increased from 2×10^-4 cm· s^-1to 1.7×10^-4 cm·s^-1 with normal oat growth,which could effectively improve the moderate soda soil salinization.