In this paper, MDY-2electronic densitometer and Germany DCAT21automatic surface tension meter are used to measure the density and surface tension over the whole concentration range (the molar fraction of ionic liquids in oganic solvents is 0~1) for the binary mixtures of ionic liquids N-butylpyridinium nitrate (NO₃) and organic solvents such as methanol,ethanol and butanol at the temperature of 298.15K. The excess molar volumes VE and the surface tension deviations δγ of binary mixtures {NO₃₊CH₃OH},{NO₃₊C₂H₅OH} and {NO₃₊C₄H₉OH} are determined. VE and δγ are fitted by using the Redlich-Kister equation. The results show that the excess molar volumes of binary mixtures of {NO₃₊CH₃OH} and {NO₃₊C₂H₅OH} are negative over the whole composition range, while the VE of binary mixture {NO₃₊C₄H₉OH} has positive values at low molar fraction of ionic liquid, passing through a maximum and then decreases and becomes negative, showing minimum at higher ionic liquid molar fraction. The surface tension deviations δγ of 收稿日期:2012-05-04；修回日期:2012-09-05；责任编辑:张士莹 基金项目:国家自然科学基金资助项目(20776037)；河北省自然科学基金资助项目(B2012208084) 作者简介:王建英(1973- ),女,河北灵寿人,副教授,博士,主要从事离子液体方面的研究。 通讯作者:胡永琪教授。E-mail:huyq@hebust.edu.cn {NO₃₊CH₃OH} systems are positive, but those of {NO₃₊C₂H₅OH} and {NO₃₊C₄H₉OH} systems are negative over the entire molar fraction range. It seems that surface tension deviations δγ varys from positive to negative with the increase of alkyl chain length of alcohols.