A solenoid valve and a manufacturing method are disclosed. The solenoid valve includes a main body portion, a movable iron core, a valve portion, a lower cover and an upper cover. Wherein the main body portion includes a bobbin, a fixed iron core, a magnetic conductive portion, a coil and an outer case. The outer case covers the bobbin, the fixed iron core, the magnetic conductive portion, and the coil. The movable iron core is movable relative to the fixed iron core, and the lower cover is disposed in the valve portion. A left side surface of the upper cover is fixed at the valve portion and the lower cover, and a right side surface of the upper covers is fixed at the main body portion. The solenoid valve has stable size and stable operation, and can quickly cut off the air pressure, and the control effect is good.