Abstract: DLP lithography printing has high application value in the field of 3D printing due to its high printing efficiency and molding accuracy, and in some scenarios that require the use of 3D printing, such as model manufacturing, when larger objects need to be printed, it is impossible to use a single optical machine to complete the large format due to the limitation of DMD chip size. In order to solve this problem, multi-optical machine splicing printing is used, and the large-size slice is divided into two optical machines for splicing and printing, and then the grayscale at the seam is adjusted to achieve larger-size printing. After experiments, it can be seen that the accuracy and strength of splicing printing are better, and the printing area is expanded from 150 mm×120 mm to 150 mm×237 mm.