Provided is a 3D printing method. The method comprises the steps that a sending end system splits a 3D printing source file layer by layer according to the printing sequence and stores the 3D printingsource file into a plurality of 3D printing sub-files, the plurality of 3D printing sub-files are sequentially sent to an execution end system according to the printing sequence, and after sending ofeach 3D printing sub-file is completed, the 3D printing sub-files are deleted; and the execution end system receives and stores the plurality of 3D printing sub-files, the plurality of 3D printing sub-files are sequentially printed by 3D printing equipment, and after printing of each 3D printing sub-file is completed, the 3D printing sub-files are deleted. Each system or device does not have a complete 3D printing file at the same time. In the printing process, the whole system does not have the complete 3D printing file, so that the safety of the 3D printing file is greatly improved, and thetechnical leakage risk is greatly reduced.