Diploma thesis is focused on a conceptual design of a double acting hydraulic amplifier designed for demolition tools of mobile work machines. In the beginning, there is a theoretical description of function of linear hydromotors, Further principle described in the thesis is a hydrostatic transfer of force, the description and the function of hydraulic amplifiers and their division into individual types, which are described in more detail. After basic principles description, there is state of art of hydraulic amplifiers, which is implemented on the basis of the patented databases.In the core of the diploma thesis, the analysis of the current state of art in the field of hydraulic amplifies is stated. Chosen hydraulic amplifiers are compared after analysis according to specific parameters. The next thing proposed is a conceptual design of double-acting hydraulic amplifier for integration to piston rod of mobile work machines. Simulation model is made according to the conceptual design of the hydraulic amplifier, on the basis of which the function of the amplifier will be verified and the parameters monitored.In the final part of the diploma thesis, there is a proposed process of testing of the double-acting hydraulic amplifier.