The article examines the structural chart of hydraulic cylinder which enables to get symmetry of speed and pull characteristics during reversible work. The study offers a development of nonlinear mathematical model of electro-hydraulic servo power drive, containing this hydraulic cylinder in the structure. Calculation researches of dynamic and static characteristics are conducted at the different signs of entrance signal. The estimation of influence of row of design factors of hydraulic power drive is executed for the similarity of transients in it and the symmetry of speed characteristics during reversible work. The study shows that at a certain correlation of the positive ceilings of pressure and return choke cracks of slide-valve of electro-hydraulic power-amplifier, the identity of dynamic and speed characteristics of hydraulic servo power drive is provided with acceptable preciseness.