Two difficult problems which are drilling string vibration and drilling pressure control exist in the process of drilling large displacement horizontal well. Using hydraulic thruster can not only improve the mechanical drilling speed and increase the horizontal section of footage displacement but also obtain better drill string dynamic characteristics and reduce vibration of drilling tool and prolong the life of the bottom hole assembly. By using the spring-damping model of drill string, the dynamic response of the different excitation of the drill bit is analyzed, so as to evaluate the effect of vibration reduction of hydraulic thruster. Use the three factors four levels orthogonal test method to optimize the key design parameters of hydraulic thruster. The analysis shows that the different drilling mud density should be used in the hydraulic thruster with different key parameters, in order to display its superiority.