Due to the high gain of the roll transfer function of the multi-domain small-caliber guided rocket, the classic PID control method has poor anti-induced rolling moment capability, which is manifested by the fact that the roll angle responds to a long time away from the roll command and the roll rudder deflection angle is small. To solve this problem, a robust roll angle control method based on linear extended state observer (LESO) is proposed. Through the LESO, the modeling error, internal and external disturbances of the controlled object are estimated in real time and dynamically compensated, so that the controlled object is converted into a series integrator. Considering the effect of the second-order model of the actuator and the lag of the LESO, the frequency domain design is carried out, and a correction network is added to the disturbance compensation loop to improve the stability margin. Numerical simulation shows that the proposed method can effectively suppress the influence of roll disturbance moments and improve the robustness of roll autopilot.