The invention relates to the field of preparation of nano/micro-materials, and particularly relates to an external adjustable radial expanding annular space combined nozzle for supercritical fluid prepared nano/micro-materials. The external adjustable radial expanding annular space combined nozzle is composed of a nozzle core, a conical end sleeve, a core adjusting cylinder, a sleeve adjusting cylinder, a spherical face sleeve, a main adjusting ring, a secondary adjusting ring, a crystallizer end part, a sealing ring, a roll bead, a fluid connecting pipe, a fastening bolt, an adjusting ring locking nut, a spherical face sleeve locking nut and a limiting screw. According to the requirement of the preparation technique of the supercritical fluid prepared nano/micro-materials, above members are selected to assemble a single-channel combined nozzle or a dual-channel inside or outside mixing combined nozzle or a three-channel inside or outside combined nozzle or a three-channel inside outside or outside inside mixing combined nozzle. The external adjustable radial expanding annular space combined nozzle reduces the processing cost, improves precision, uniformity of every annular gap ofthe nozzle and the nozzle dredging effect, realizes the external adjustment of the crystallizer of the nozzle annular gap, and eliminates the influence of increased annular gap distance caused by increase of annular gaps on the crystalizing process of the prepared material.