The invention relates to the technical field of 3D printing equipment, in particular to a 3D printing achieving method, a printing system and a jet flow control method under the microgravity environment. A glue sprayer and a pressurizing sprayer are arranged, the glue sprayer sprays a layer of glue in the program assigned area firstly, and then the pressurizing sprayer melts hot melting wires and increases conveying. After the molten spraying wires are extruded out, bonding forming is carried out under the microgravity state. The flow of molten spray wires and the extruding bonding forming process are controlled by controlling the movement of the pressurizing sprayer. Accordingly, solid printing is achieved. The 3D printing purpose under the microgravity space environment is achieved. The 3D printing achieving method, the printing system and the jet flow control method can be used for 3D printing under the space environment.