Abstract: Based on slurry extrusion, direct-ink-writing (DIW), which is a simple and cost-effective 3D printing technology, enables the manufacturing of parts with fine and complex three-dimensional architecture under a mild condition. Accordingly, it has great potential and opportunities in the field of advanced ceramic preparation. However, DIW is currently facing problems such as lack of materials and difficulty in the preparation of suitable slurry, hindering its practical and commercial applications. In view of this, a new type of DIW 3D printer based on air pressure was developed in this work. On this basis, a titanium dioxide (TiO₂) ceramic slurry suitable for direct writing molding was prepared by using TiO₂ as raw material and polyvinyl alcohol (PVA) as a flow aid as well as a binder. The effect of PVA contents on the rheological behavior of the slurry and the DIW printability was systematically studied. Subsequently, TiO₂ parts with complex shapes and structures were constructed successfully. The cross-sectional morphologies, printing accuracy as well as the shrinkage of the as-printed parts after sintering was further investigated. The results show that PVA can effectively reduce the viscosity of the slurry and improve its fluidity, which is beneficial to improve the 3D printability, and promote the adhesion between adjacent layers of the printed part. However, ceramic slurry with PVA content above 10wt% could suffer from slump during the deposition stage. With the increasing PVA content, the vickers hardness of the sintered parts decreases, and the shrinkage of the as-prepared parts increases.