Abstract: The aim of this paper is numerical analysis of the finite waves interaction in water. The mathematical model is built on the basis of Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation. The problem is considered as an axial symmetric one. The finite-difference method has been used 10 solve the KZK equation. The paper presents the mathematical model and some results of numerical investigations of finite amplitude waves interaction. One shows the waveform and spectrum of the wave for fixed distances from the source, and (he pressure amplitude changes as a function of distance of different harmonic components.