Density and viscosity are essential physical properties and need to be well-known in chemical engineering design as well as process optimization. To expand the potential application of ILs, it is important to know the properties of ILs mixtures for their widely used. In this work, the values of density and dynamic viscosity of aqueous [C(3)py][DCA] with the molarity range from (0.0500 to 1.0096) mol kg(-1) were measured at T = (288.15-318.15) K. In terms of Jones-Dole equation, the viscosity B-coefficients with large positive value and dB/dr < 0 were obtained and it implied that the ionic liquid is water-structure-making. The values of the contribution per mole of the solute to the free energy of activation for viscous flow of the solution, Delta m(2)(not equal 0), were obtained on the basis of the Feakins' theory. The relationship between Delta mu(not equal 0)(2) and temperature is linear so that standard molar activation entropy Delta S-2(not equal 0) and enthalpy, Delta H-2(not equal 0), were obtained. At constant molality, Delta H-2(not equal 0) is a temperature-independent constant so that implies the activation process of the solute for viscous flow of aqueous [C(3)py][DCA] is an isocoulombic reaction. According to Eyring's theory, a semi-empirical method to predict the viscosity of aqueous [C(3)py][DCA] was put forward and the predicted values are all most the same with corresponding experimental ones. (C) 2017 Elsevier B.V. All rights reserved.