The paper presents the results of the study on the hydrodynamics and heat transfer in the cavities in a liquid-cooled cylinder head of a high- accelerated diesel engine using numerical simulation. The cooling cavity of the cylinder head is a key element of the cooling system, as it is where the processes of heat transfer from the bottom of the combustion chamber, valves and the discharge passage into the coolant occur. Using a complex of modern software allowed us to obtain the basic parameters of fluid motion and heat transfer, as well as to provide a visual assessment of flow patterns in order to identify the problem areas. Application of the developed methods makes it possible to clarify the definition of the temperature field of the cylinder head, and ensure the reduction of the maximal temperatures and the alignment of the temperature field. The basic calculation is carried out in the Flow Simulation (COSMOSFloWorks) software, which is part of the SolidWorks complex.