In this work, PDC SiOC porous structures were fabricated using the stereolithography (SLA) 3D printing method with preceramic resin methylsiloxane. The printed structures were then sintered at 1000 °C for 1 h. Water treatment can help prevent the shrinkage and remove the unreacted resin. From the XRD and FT-IR results, the sintered ceramic is amorphous SiOC. The microstructures show that the printed structures have high geometric accuracy. The water reinforcement process produces smoother surfaces on the printed structures.