To solve the problem that the response of the walking platform of bricklaying robot is slow and uncertain factors such as load change and friction of hydraulic cylinder affect the adjustment accuracy, an electro-hydraulic servo system with four hydraulic cylinders is designed. The system is an improved ADRC method. The available information of the whole system is fully considered, and the piston rod position deviations of the hydraulic cylinder is taken as the input of the whole controller to reduce the phase lag caused by the extended observer and improve the response speed of the control system. The position deviations of the piston rod in a cylinder is compensated by observation, and the high-order term and uncertain disturbance in the whole control system are defined as total disturbance, so the structure of the controller is simplified appropriately. Finally, MATLAB and AMESim are used for simulation analysis. The simulation results show that the improved ADRC method can significantly improve the response speed of the system and the suppression of uncertain disturbance. This research provides a theoretical basis for the research of masonry robot mobile platforms.