As a new generation of functional ionic liquid,amino acid ionic liquids(AAILs)have the ability to form strong hydrogen bonds,dissolving the DNA,cellulose and other carbohydrates,so it can be widely used as chiral solvents and new functional materials in life science research and the pharmaceutical industry.This paper we report that the enthalpies of solution and the density for [C4mim][Ala] were measured at(288.15 to 308.15 ± 0.01)K with an interval of 5 K by a solution-reaction isoperibol calorimeter and an Anton Paar DMA 4500 oscillating U-tube densitometer.The values of the standard molar enthalpy,ΔsolHm θ,and the apparent relative molar enthalpy,(￠)L,of solution for [C4mim][Ala] were obtained in terms of Archers method.The standard molar heat capacity of solution,ΔCp,m θ = 590 J·K-1·mol-1,for [C4mim][Ala] was obtained from the slope of the straight line of ΔsolHm θ vs.(T – 298.15)K.The apparent relative molar heat capacity of various molalities [C4mim][Ala] were estimated by Archers theory and Paulechkas method.In addition,the hydration enthalpy of the alanine anion [Ala]-,ΔH–([Ala-])= – 395 kJ·mol-1,is obtained.