Abstract: The modelling of surface and volume backscattering of a single-beam echosounder signals on sea floor using impulse response approach is presented. Kirchhoff (tangent plane) approximation is used in surface scattering modelling for approximately fiat sea bottom and small perturbation theory is applied to describe the volume backscattering. The influence of bottom physical features as well as the system parameters (operating frequency, beamwidth) on the shape of the sea bed impulse response and echo waveform is investigated. The results have revealed the differences for particular cases of bottom and acoustic system's parameters and they are important for validation of newly developed algorithms of echo signals processing for bottom classification.