The utility model relates to an automatic liquid-draining system for the separator in the natural gas station, which is applied in the automatic liquid-draining system of the separator in gas field and includes a separator (1), an electric ball valve (3), a water meter (4) and a natural gas water drain valve (5); the natural gas water drain valve (5) is communicated with the electric ball valve (3), the water meter (4) is communicated with the natural gas water drain valve (5). The separator (1) is arranged on the top of the device, the maintenance and replacement are simple, convenient and needs no debugging, which decreases the field maintenance work amount of the specialized technical personnel on the automatic instrument; the device has low failure rate and long service life, which decreases the work amount of the operator in the gas gathering station; the device has strict gas prevention measures, which prevents the high-pressure gas from entering the wastewater tank, thus reducing the safety risk; the service life of the electric ball valve is prolonged, which reduces the manual draining operation of the operator in the gas gathering station, decreases the field maintenance work amount of the specialized technical personnel on the automatic instrument, prevents the high-pressure gas from entering the wastewater tank and reduces the safety risk.