Ionic liquids (ILs) existing as liquid state at room temperature are composed of a immense heterocyclic cation and inorganic anion which is smaller than cation's size . Thus, the species of cation and anion as well as the length of alkyl group on the cation have influence on their physical properties. Their outstanding properties such as non-volatility, thermal stability and wide range of electrochemical stability make these materials excellent candidates for green solvent which can substitute the conventional organic solvents. In this study, ILs based on imidazolium cation have been synthesized such as 1-butyl-3-methylimidazolium bromide ([BMIM][Br]), 1-butyl-3-methylimidazolium chloride ([BMIM] [Cl]), 1-butyl-3-methylimidazolium iodide ([BMIM][I]), and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]). The density, viscosity, refractive index, heat capacity and ionic conductivity of [BMIM][Br], [BMIM][I], and [BMIM] [BF4] were measured over range of temperature of 293.2 to 323.2 K. The density and refractive index values of [BMIM][I] were the highest among three ILs and the viscosity values of [BMIM][Br] were the highest among three ILs. The heat capacities [BMIM][BF4] were higher than those of [BMIM][Br]. The ionic conductivities of [BMIM][BF4] were higher than those of [BMIM][I].