As technology improves by leaps and bounds,functionally gradient materials can better meet the needs of practical applications,such as laser ceramics with gradient doping can well alleviate the thermal effects.However,it is often difficult to prepare gradient structural materials by traditional methods.3D printing has the ability to form complex structures and can be well adapted to the preparation of functionally gradient materials.In this paper,an active mixing printhead based on direct ink writing for 3D printing laser ceramics is proposed,and pure YAG and 0.25 at% Yb:YAG slurries are selected to verify the mixing performance of the printhead.Firstly,the rheological properties of the two slurries are investigated.Then,the mixing process is simulated by computer fluid dynamics (CFD)using Ansys Fluent software to explore the effect of mixing speed on mixing uniformity.In addition,the distribution of Yb elements on the extrusion lines section of the printhead at different mixing speeds are detected by SEM andEDS mapping and theexperimental results are compared with the numerical simulation results to verify the correctness of the simulations.Finally,the gradient doped Yb:YAG laser ceramics are successfully fabricated by combining the printhead with a direct ink writing device.In conclusion,direct ink writing with active mixing provides more possibilities for gradient doped Yb:YAG laser ceramics fabrication.