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The paper considers a problem of dynamic impact of hoisting mechanisms, which are based on the multistage hydro-cylinders, on the hoisted object. Hydro-cylinders have high specific characteristics, but there are also some drawbacks. One of them is an impact at the beginning and at the end of hoist and in switching the stages. And in case of switching the stages under certain conditions the impact in nature can be a high impact impulse. The paper explores the impacts at the beginning of hoist and when switching the stages. Numerical modeling is assumed to be a method of study. To build a mathematical model the following factors have been considered: geometrical cylinder parameters, hydraulic liquid compressibility, and friction between cylinder elements. Elasticity of ground, elasticity of rod, and elasticity of cylinder walls have been ignored. The modeling results allowed us to reveal a hydraulic nature of the stage-switching impact, introduce a formula to estimate the impact impulse value, show the friction effect on the impact impulse value and give a proposal to use a counter-pressure chamber to eliminate the stage-switching impact. An expression for the optimal counter-pressure is presented. The results obtained can find application in designing the new and upgrading the existing hoisting multistage hydro-cylinder mechanisms to increase a hoisting speed and simultaneously eliminate the impact on hoisted object. Compared to existing papers in the field concerned, this one concentrates on revealing a specific hydraulic nature of the stage-switching impact, without regard to dynamics and elasticity of the hoisting mechanism parts other than the cylinder itself. The achieved results find confirmation when compared to the numerical and field data published by other authors.