Abstract: An inverted pendulum with flexible joints is modeled and controlled using LQR algorithm. First, a mathematical model for an inverted pendulum with flexible joints is proposed. It is theoretically proved that open-loop control systems are unstable, but they are controllable on equilibrium point. Secondly, an educational experiment system is realized so that the hardware of the flexible joint inverted pendulum is controlled through Matlab and Simulink, followed by discussions on how to select the parameters of the weight matrices Q and R . Finally, a networked remote control system is also realized. It is programmed with Matlab and C language.