Abstract: Percutaneous interventional thermal ablation has become the third major radical treatment for liver tumors, following surgical resection and liver transplantation. Thermal ablation therapy is a minimally invasive treatment in which the ablation applicator (ablation needle) is percutaneously inserted into the lesion area under the guidance of medical imaging, so as to kill cancer cells in situ. Accurate and effective needle trajectory planning is the key to microwave/radiofrequency ablation of liver tumors. However, in clinical thermal ablation treatment, the needle trajectory planning still depends on the personal experience of doctors. Therefore, in recent years, computer-aided needle trajectory planning has become a research hotspot in the field of thermal tumor ablation. Its goal is to assist doctors to develop personalized surgical strategies to achieve "conformal" treatment of liver tumors and improve the safety and efficacy of thermal ablation therapy. This paper systematically reviewed the computer-assisted needle trajectory planning algorithms for microwave/radiofrequency ablation of liver tumors. The research progress and limitations of ablation needle trajectory planning algorithm were introduced and discussed at multiple levels, from single clinical constraint to multiple clinical constraints, from single ablation applicator intervention to multiple ablation applicator collaborative intervention, and from rigid trajectory planning to elastic trajectory planning. Future developments are suggested.