Abstract: The aim of this work is to present the preliminary results of the layer thickness assessment method based on the optimization approach. The developed method is based on a multilayer model structure. The measured acoustic signal reflected from the layer is compared with a simulated signal on the basis of the multilayer model. The cost function is defined as the difference between the reflected signal measured using the pulse echo approach and the simulated signal. The thickness of the solid layer is the parameter which minimizes the cost function yielding the desired solution. Minimization of the cost function is performed with the use of the simulated annealing algorithm. The results obtained with the developed method using the measurement data of a custom design model are compared with the reference value and the accuracy of the method is verified. The relative error of the thickness estimation is 1.44%.