**Abstract**

Pediatric oncological surgery is difficult and challenging, especially in children with malignant solid tumors. Compared with adults, children have immature organs, thin blood vessels, and poor surgical tolerance. Moreover, pediatric malignant solid tumors are often huge, complex in location, fast-growing, and highly malignant. With artificial intelligence and machine learning breaking through many bottlenecks, computer-assisted precision medicine has also taken a quantum leap forward. Ten years ago, Professor Dong's group invented the Computer-assisted Surgery System (Hisense CAS). Now, this three-dimensional (3D) visualization technology based on artificial intelligence has been used for pediatric precise oncological surgery and has been upgraded to version 5.0. Hisense CAS was developed based on enhanced pediatric CT data, so it has advantages in displaying pediatric solid tumors. CAS can display the adjacent relationships of the tumor with the surrounding tissues (especially the compressed blood vessels) in a 3D, dynamic, and complete manner through rapid and accurate 3D reconstruction of organs, tumors, and blood vessels. Then, precise preoperative evaluations and surgical planning can be carried out. This chapter focuses on individualized computer-assisted surgical planning and progress in common and complex pediatric tumors (such as malignant liver tumors, retroperitoneal tumors, and mediastinal tumors) and introduces experience in improving the resectability of tumors and reducing surgical complications.

**Keywords:** tumor, surgery, pediatric, computer-assisted, precise surgery
