Three dimensional (3D) printing technology by direct ink writing (DIW) is an innovative complex shaping technology,possessing advantages of flexibility in fabrication,high efficiency,low cost,and environmental-friendliness.Herein,3D printing of complex alumina ceramic parts via DIW using thermally induced solidification with carrageenan swelling was investigated.The rheological properties of the slurry under different thermally-induced modes were systematically studied.The solidification properties of thermally-induced pastes with varying contents of earrageenan were optimized.The experimental results showed that the optimized paste consisting of 0.4 wt% carrageenan could be rapidly solidified at about 55 ℃,which could print inclined-plane more than 60° in vertical without support,resulting in better homogeneity of the green body.A nearly pore-free structure was obtained after sintering at 1600 ℃ for 2 h.