The flight environment simulation intake system is a key subsystem for testing the high-altitude performance of aircraft engines on Altitude Ground Test Facility, requiring it to accurately simulate the engine’s high-altitude environment (i.e. pressure, temperature). This article focuses on the intake system with strong coupling and disturbance characteristics, and designs a multivariable robust H∞ controller to achieve high-precision control of intake pressure and temperature. Firstly, a linear model of the intake system is established using the small deviation linearization method, and an augmented model is constructed by combining it with the dynamic model of the regulating valve. Then, considering the dynamic response performance and disturbance rejection performance of the closed-loop system, an optimization problem for controller design is established based on linear matrix inequality (LMI). To further improve control performance, particle swarm optimization method is introduced to achieve good pole configuration of the closed-loop system. Finally, simulation tests were conducted on the tracking and disturbance rejection performance of the intake system, and compared with traditional PI controller to verify the superiority of the multivariable robust H∞ controller designed in this paper.