A four-step Jerk circuit comprises a three-step chaotic circuit, and a Jerk junction is connected in the three-step chaotic circuit to form the four-step Jerk circuit. The Jerk junction comprises an operational amplifier U5, resistors R7, R8 and R9, and a capacitor C4. The non-inverting input end of the operational amplifier U5 is grounded, the capacitor C4 and the resistor R8 are connected between the inverting input end of the operational amplifier U5 and the output end of the operational amplifier U5 in parallel, the output end of the operational amplifier U5 is connected with the inverting input end of an operational amplifier U1 in the three-step chaotic circuit through the resistor R9, and the inverting input end of the operational amplifier U5 is connected with the output end of an operational amplifier U3 in the three-step chaotic circuit through the resistor R7. The four-step Jerk circuit can output four chaotic signals, produce six phase diagrams, enable topological structures attracted by the circuit in a chaotic mode to be more difficult to recognize, and enable chaotic dynamics behaviors to be more complex. The chaotic circuit applied in chaotic secret communication can further improve secrecy performance of the chaotic system and increase cryptanalysis difficulty.