[Objective]To investigate the application of robotic arm guided by celestial eye computer surgery system in tibial precise osteotomy in unicondylar knee arthroplasty (UKA). [Methods]20 patients with medial-compartment osteoarthritis of the knee received surgery. CT data of patients were collected before operation, and then imported into the celestial eye system to select appropriate prosthesis and plan the position of prosthesis. During the operation, a computer guided mechanical arm was used to insert three Kirschner wires into the proximal tibia, perform precise osteotomy along the direction of the Kirschner wires, place matching prostheses, and perform computer guided UKA surgery. The postoperative knee function and imaging data were followed up 6 months after operation to evaluate the surgical effect. [Results]All 20 patients successfully completed the operation. The average operation time was 48.50 ± 8.60 minutes, and the average blood loss was 47.50 ± 10.07 ml. No serious complications occurred 6 months after operation. The range of motion of the knee and the clinical and functional scores of KSS were significantly improved compared with those before operation (P<0.05). The posterior tibial slope, varus and varus, internal and external rotation angles of tibial prosthesis and tibial osteotomy thickness after operation were no significant difference contrast to those of preoperative planning (P>0.05), suggesting that the tibial prosthesis has a high accuracy of position. [Conclusion]The use of the celestial eye computer surgical system to guide the robotic arm to perform precise tibial osteotomy in UKA is effective and convenient, which has strong clinical translation and promotion value.