Previous investigators demonstrate that the impact performance of the drifter is affected by the forces such as viscous friction resistance and axial thrust of liquid. In this research, some other forces including hydraulic sticking force, sealing resistance, steady flow force and transient flow force are also taken into the consideration to develop a non-linear mathematical model of the dualchamber-controlled hydraulic drifter. We take piston mass, supply flow rate, supply pressure and the front and back work areas of the piston as the main design parameters to predict the impact efficiency of the drifter using the controlling variable method. The result shows that the impact efficiency decrease as the increasing of the piston mass or supply flow rate. The impact efficiency reaches a peak value 0.48 when the supply pressure P ranges from 150 to 230 bars. The decrease of the front work area A1 of the piston, as well as the increase of the back work area A2, would improve the impact efficiency. With the combination of the design parameters P, A1 and A2, there is a high efficiency area 162.5 < P < 230 bars and 0.48 < A1/A2 < 0.86 with the impact efficiency value 0.46–0.495.