The invention discloses a dual-source intelligent steering system for an electric passenger car, which comprises an environment sensing unit, an upper-layer controller, a lower-layer controller, a first inverter, a second inverter, a 48-volt low-voltage storage battery connected, a high-voltage power battery pack A phase-connected, open-winding permanent magnet synchronous motor, a reducer, a torque sensor, a steering tie rod, a steering tie rod, a ball screw and a steering transmission mechanism, and each steering transmission mechanism is respectively connected to a steering wheel. The invention also discloses a steering cooperative control method, including a vertical and horizontal cooperative self-evaluation optimization decision-making method and a high-low dual-source master-slave cooperative control method under multiple performance objectives. The invention provides a basis for realizing L4 level automatic driving, which can not only meet the high power demand of electric passenger cars when turning, but also use high and low voltage dual power sources to work together to reduce power consumption when turning, save energy, and have higher reliability and will not Make the electric passenger car turn to the accident because of single power source failure.