Linear matrix inequalities (LMI) method is proposed to design the robust controller for the servo-hydraulic actuator with parametric uncertainties. The pretreatments are adopted to convert the nonlinear dynamic models into linear state equations using the linear fractional transformation (LFT) approach, which facilitates conveniently utilizing the LMI method to calculate the state feedback controller. The supervising parameters, including the system output and special derivative output generated from the uncertain items, are proposed to model a state matrix equation for representing the dynamic system with the parameter variations and disturbances. LMI control base on the H∞ control schematic is finally employed to carry out the state feedback controller for the servo-hydraulic actuator with parametric uncertainties. The results demonstrate the efficiency of dynamical performance with small settling time and overshoot compared with the quantitative feedback theory (QFT) approach.