A method of manufacturing a water inlet solenoid valve configured to enhance an electromagnetic suction force, comprising: obtaining a plastic-sealed stator assembly by injecting plastic on a stator assembly, comprising: mounting an upper magnetic conductive inner sleeve and a lower magnetic conductive inner sleeve in a hole of a coil assembly; injecting plastic on an inner surface of the upper magnetic conductive inner sleeve and the lower magnetic conductive inner sleeve, configured to form a water-isolating sleeve on the inner surface of the upper magnetic conductive inner sleeve and lower magnetic conductive inner sleeve; mounting a yoke outside the coil assembly and connecting the yoke with the upper magnetic conductive inner sleeve and the lower magnetic conductive inner sleeve; mounting a magnetic conductive seat on an inner side of the water-isolating sleeve; injecting plastic on the coil assembly and the yoke, configured to form a plastic-sealed layer configured to cover the coil assembly and to tightly connect the yoke with the upper magnetic conductive inner sleeve and lower magnetic conductive inner sleeve; assembling the plastic-sealed stator assembly and a valve body assembly comprising a movable iron core together to form the water inlet solenoid valve; wherein an upper end face of the movable iron core at an initial position is slightly higher than an upper edge of the lower magnetic conductive inner sleeve; wherein the upper end face of the movable iron core at an initial position is set as not lower than the upper edge of lower magnetic conductive inner sleeve and not higher than 1/4 of the distance from the upper edge of lower magnetic conductive inner sleeve to the lower edge of upper magnetic conductive inner sleeve, so as to enhance the electromagnetic suction force of the solenoid valve for water. mounting an upper magnetic conductive inner sleeve and a lower magnetic conductive inner sleeve in a hole of a coil assembly; injecting plastic on an inner surface of the upper magnetic conductive inner sleeve and the lower magnetic conductive inner sleeve, configured to form a water-isolating sleeve on the inner surface of the upper magnetic conductive inner sleeve and lower magnetic conductive inner sleeve; mounting a yoke outside the coil assembly and connecting the yoke with the upper magnetic conductive inner sleeve and the lower magnetic conductive inner sleeve; mounting a magnetic conductive seat on an inner side of the water-isolating sleeve; injecting plastic on the coil assembly and the yoke, configured to form a plastic-sealed layer configured to cover the coil assembly and to tightly connect the yoke with the upper magnetic conductive inner sleeve and lower magnetic conductive inner sleeve; assembling the plastic-sealed stator assembly and a valve body assembly comprising a movable iron core together to form the water inlet solenoid valve; wherein an upper end face of the movable iron core at an initial position is slightly higher than an upper edge of the lower magnetic conductive inner sleeve; wherein the upper end face of the movable iron core at an initial position is set as not lower than the upper edge of lower magnetic conductive inner sleeve and not higher than 1/4 of the distance from the upper edge of lower magnetic conductive inner sleeve to the lower edge of upper magnetic conductive inner sleeve, so as to enhance the electromagnetic suction force of the solenoid valve for water.