Gas-sand separating device for natural gas well

A gas-sand separating device for a natural gas well comprises a plurality of sand settling cylinders, wherein main flow pipes are inserted in the inlet ends of the sand settling cylinders; the inside diameter of the main flow pipes is 1/2 to 1/5 that of the sand settling cylinders; main flow outlet pipes are inserted in the upper parts at the outlet ends of the sand settling cylinders; the front ends of the main flow outlet pipes are closed; the axes of the main flow outlet pipes are higher than those of the sand settling cylinders; a plurality of small holes are drilled in the upper semicircular cambered surfaces of the parts, inserted in the sand settling cylinders, of the main flow outlet pipes; drainage sand conveying pipes are inserted in the lower parts at the outlet ends of the sand settling cylinders; the axes of the drainage sand conveying pipes are lower than those of the sand settling cylinders; the inside diameter of the drainage sand conveying pipes is smaller than that of the main flow outlet pi