In this paper, applying frequency domain techniques based on Bode diagram, fractional-order Liu chaotic system is studied. An electronic circuit unit of tree shape is designed to realize the fractional-order chaotic Liu system. Circuit experiment of 2.7-order Liu system, as well as simulation results of fractional-order Liu chaotic system with α=0.8—0.1 in step size of 0.1， verify the circuit unit's effectiveness, and prove that chaos actually exists in the fractional-order Liu chaotic system with order as low as 0.3. A simple, but effective linear feedback controller is designed to realize the chaotic control of fractional-order Liu chaotic system.