The invention discloses an integral electric control proportional valve for an automobile diverter and a control method of the integral electric control proportional valve. The integral electric control proportional valve comprises a housing, a fixed sliding core, an oil port flange and an electromagnetic coil. The electromagnetic coil is fixed into the housing. A sealed cavity is formed by the housing, the electromagnetic coil and the oil port flange. The top of the fixed sliding core is fixed to the middle of the oil port flange. The sealed cavity is internally further provided with an adjusting base, an adjusting screw, an adjusting spring, a spring base, a movable iron core and a magnetism isolating sleeve. The adjusting base is arranged at the bottom of the cavity and fixed to the middle of the electromagnetic coil, and the bottom face of the adjusting base is fixed to the bottom face of the housing. The adjusting screw is fixed to the middle of the adjusting base, and one end of the adjusting spring is fixed to the top of the adjusting screw. The spring base is fixed to the top of the adjusting spring. The magnetism isolating sleeve is arranged on the inner wall of the electromagnetic coil. The provided proportional valve is compact in structure, low in cost and high in stability.