The invention discloses a system and method for extrusion control based on a magnetorheological fluid brake. The control system comprises a device part. The device part comprises the magnetorheological fluid brake, an electric cylinder, an elastic link and a motor. The side of a brake disc of the magnetorheological fluid brake is connected with the electric cylinder through the elastic link, the side of a rotary disc is connected with the motor, and an excitation coil is wound around the magnetorheological fluid brake. A control part comprises a microcontroller, a digital signal processor (DSP), a torque sensor, a pulse width modulation (PWM) inversion controller, a D/A converter, a frequency converter and a programmable power supply. The microcontroller is electrically connected with the electric cylinder through the PWM inversion controller and the D/A converter, the microcontroller is electrically connected with the excitation coil through the programmable power supply, the torque sensor is connected with the input end of the DSP, the output end of the DSP is electrically connected with the microcontroller, and the frequency converter is electrically connected with the motor. According to the system and method for extrusion control based on the magnetorheological fluid brake, by the application of axial extrusion force to the magnetorheological fluid brake, braking torque of the system is increased, and a braking effect is improved.