Series elastic actuators (SEAs) have excellent structural advantages and safety performance, but they also bring a series of control challenges such as high-order system dynamics and increased parameter uncertainty. In response to the requirements of accuracy, robustness and ease of use in the position control of high-performance SEA systems, this paper proposes a robust position control method based on a linear quadratic integral (LQI) tracker. This paper first establishes the dynamic model of the SEA system, introduces the LQI controller into the position tracking task, systematically derives the controller design process and performs closed-loop stability analysis. In both simulation and hardware experiments, the proposed LQI control method exhibits good tracking accuracy and robustness. The results show that this method can effectively cope with load disturbances and model uncertainties, and meet the needs of high-performance position control in practical engineering applications.