The invention relates to a gas ballast valve which solves the problems of large occupied space and high cost of an original gas ballast valve. The novel gas ballast valve is provided with a valve body and a gas inlet channel; a top body is arranged in the gas inlet channel; a filter cavity is arranged on the gas inlet channel; the filter cavity divides the gas inlet channel into an outer gas inlet channel and an inner gas inlet channel; the outer and inner gas inlet channels are not in the same straight line; an included angle more than or equal to 0 degree and less than 90 degrees is formed between the outer gas inlet channel and the inner gas inlet channel; and a detachable spacer sleeve is arranged out of the filter cavity. The gas ballast valve can be widely applied to the field of centrifugal vacuum purification.