In order to identify thermal conductivity and thermal diffusivity of the material, the thermal conductivity and the heat capacity of unit volume are identified simultaneously according to the measured temperature data based on an inverse computational model of unsteady heat conduction. A new nonlinear inversion algorithm named as chaotic optimization is introduced to solve the present computational model. The chaotic optimization method has the property of global convergence and can overcome the difficulty that exists in the damping Newton method to solve the inverse model. The precise integral method is used to solve the instantaneous heat transfer equations to improve solution precision. The efficiency of the present approach is examined with numerical examples.