Disclosed herein are a solenoid valve for a brake system and a manufacturing method thereof, to achieve easy manufacture and low manufacturing costs via a more simplified configuration than the related art. The solenoid valve includes a valve core, a sleeve into one side of which the valve core is inserted, an armature movably received in the sleeve, a seat having an orifice that is opened or closed by the armature, a return spring to press the armature toward the orifice, a filter member press-fitted in a modulator block having an inlet path and outlet path, a filter being coupled to the filter member, and a seat housing having one side press-fitted into the filter member and the other side press-fitted into the sleeve, the seat being press-fitted in the seat housing. The seat housing takes the form of a tubular member having an approximately constant thickness and is provided with a stepped portion to determine a position of the seat.