Photopolymerization 3D printing method is an effective means for the manufacturing of ceramics with highly complex-shaped structures and exceptional performance. The printed samples need to undergo heat treatment such as debinding and sintering before becoming usable final ceramic parts in various industrial applications, and the debinding process has a great impact on the properties of the printed ceramic parts. In this study, effect of the debinding process on physical properties and mechanical performance of the cordierite ceramics prepared by DLP photopolymerization 3D printing was studied, and defect suppression strategy was established accordingly. The effects of debinding atmosphere and heating rate on surface cracks and material elemental distribution of ceramic samples were compared and analyzed. The microstructure, size shrinkage, relative density, and mechanical performance such as bending strength of the sintered samples were also studied. It is found that the debinding atmosphere has the most significant influence on the properties of the sintered samples, in which the surface cracks can be significantly reduced, and the relative density, and bending strength can be increased when the debinding process is conducted in argon atmosphere at the optimized heating rate of 1 ℃/min. After debinding and sintering, the cordierite ceramic samples with a relative density of (94.6±0.3)% and a bending strength of (94.3±3.2) MPa was obtained. In conclusion, this study provides a scientific basis and technical reference for fabrication and application of cordierite ceramics based on photopolymerization 3D printing method.