Disclosed herein is a solenoid valve for a brake system to reduce manufacturing costs via a shorter length and more simplified configuration of a magnet core. In the solenoid valve for a brake system to be mounted in a bore of a modulator block having an inlet and an outlet, the solenoid valve includes a magnet core having a center longitudinal penetrating hole and an entrance and exit for oil flow, an armature movably provided at one end of the magnet core and serving to open or close the exit, a valve seat provided at the other end of the magnet core, and a sleeve in which the armature and magnet core are received, the sleeve being fixed to the bore.