The invention belongs to the technical field of preparing a metal powder material and provides a gas atomization preparing method for micro spherical metal powder and equipment thereof. The preparing method comprises the technological process of smelting a material, driving molten metal jet flow through positive pressure, atomizing gas, carrying out cooling, collecting powder, detecting performance, and carrying out screening, packaging and the like, by reducing the outlet hole diameter of a flow guide nozzle, inert gas is reversely filled into a smelting chamber to certain positive pressure, the smelting chamber in the gas atomizing equipment is designed into a pressure container, a locking sealing device is adopted in the connecting portion of a furnace cover and a furnace body, the smelting chamber and an atomizing tank are designed into cavities which are isolated mutually and communicate only through the flow guide nozzle, and the fine powder yield of the metal powder is effectively increased. Compared with the existing gas atomizing metal powder preparing technology, the fine powder yield of the metal powder prepared by the utilization of the method is high, size distribution is narrow, the sphericity degree is good, the oxygen content is small, atomized gas consumption is low, and the technology equipment is simple, high in continuity and suitable for industrialized production and can be widely applied.