In this paper, the resin-based diatomite slurries for stereo lithography apparatus were successfully developed. The effects of dispersant types, content and solid content on the rheological properties of diatomite slurries were systematically discussed, and the mechanism of dispersant was analyzed. The diatomite slurries with high solid content and low viscosity for stereo lithography apparatus were obtained, and diatomite porous ceramics with complex structure were prepared by 3D ceramic stereo lithography equipment. Results show that BYK2009 is the best dispersant for diatomite slurries, and the viscosity is the lowest when the dispersant is 3% relative to the powder mass. Diatomite slurries with 40% (volume fraction) powder are prepared, and the viscosity of diatomite slurry is 17.30 Pa·s at the shear rate of 30 s-1. Diatomite porous ceramics sintered at 900 ℃ have apparent porosity of 51.30% and bending strength of (46.28±2.63) MPa. This study provides a reference for preparing diatomite carriers with complex porous structure based on stereo lithography apparatus.