The invention relates to the technical field of casting, in particular to a manufacturing method which is high in manufacturing precision and capable of improving the casting quality and is provided with a direct-cooling chilling block and used for a 3D printing core. The manufacturing method sequentially comprises the following procedures of core structure designing, core 3D printing and core flow painting. The manufacturing method is characterized in that in the core structure designing process, a pit for installing the chilling block in a matched manner is designed on a core part needing the chilling block to be arranged, and a sealing cover which is integrally formed with the core and protrudes a casting outline corresponding to the core is arranged at the position, corresponding to a casting opening, of the pit; in the core 3D printing process, the core with the sealing cover is printed through 3D printing equipment; and then, core flow painting is carried out, after a flow coating layer on the surface of the core is dried, chilling block is installed, during installation, the protruding sealing cover is polished so that an opening, corresponding to the casting side, of the pit can be exposed, sand in the pit is removed, then, the chilling block is arranged in a matched manner and fixed into the pit, finally, a fire-proof coating is painted to the exposed chilling block end face in a supplementation manner, and manufacturing of the 3D printing core with the chilling block is completed.