Abstract: Based on the LMI (Linear Matrix Inequality) method,the PID (Proportional Integral Derivative) control law was combined with robust control technique,and the subsection switch skill of PI output feedback control design with constraint of control input for aero-engine was proposed.The technology was applied to the steady state control of the full function digital electronic control system of a jet engine.The constitution of the system,including hardware,software,step motor actuating mechanism and fuel metering device,was introduced.Electronic controller not only can control the rotating speed stable but also have enough logic,multiple control monitor and protective functions.It fulfills all requirements of multiple FADEC control.The designed electronic controller has been carried through robust validity check on the engine semi-hardware-in-loop simulation platform.