Abstract: Objective: To investigate the efficacy and safety of CT-guided percutaneous liquid nitrogen cryoablation technique in the treatment of lung malignant tumors in the elderly. The focus is on analyzing the differences in the efficacy of this technique in different lesion types and treatment objectives (radical vs. palliative), as well as its impact on patients' quality of life and postoperative recovery. Methods: The clinical data of 56 elderly patients with lung malignant tumors who underwent CT-guided percutaneous liquid nitrogen cryoablation from January 2023 to December 2023 at the Second Affiliated Hospital of Nanjing Medical University were retrospectively analyzed. The patients were ≥65 years old, including 44 males and 12 females, with a mean age of 76.4±8.3 years. They were divided into radical ablation group (49 cases) and palliative ablation group (7 cases) according to the purpose of treatment. All patients underwent detailed imaging examination and functional assessment before surgery, and the lesions were precisely localized under CT guidance using a cryoablation needle during the procedure. Postoperative follow-up was performed at 1, 3, and 6 months, respectively, to assess the ablation efficacy by the modified solid tumor efficacy evaluation criteria (mRECIST), and to record the intraoperative and postoperative complication rates, pain scores (VAS), changes in C-reactive protein (CRP), and quality of life scores (ECOG). Results: All 56 patients successfully completed the procedure with no serious intraoperative complications. Postoperatively, 16 cases (28.57%) developed pneumothorax, including 10 cases with mild pneumothorax (17.9%) and 6 cases with large pneumothorax (10.7%). All pneumothorax cases were treated conservatively or with chest tube drainage and recovered well. The postoperative pain scores were 4.5±1.2 on day 1, significantly decreased to 2.5±0.8 by 1 week, and further reduced to 1.3±0.5 at 1 month. CRP levels significantly increased to 45±10 mg/L on postoperative day 1, decreased to 20±8 mg/L at 1 week, and returned to near baseline levels (12±4 mg/L) at 1 month. Curative ablation group: The complete response (CR) rate at 1 month was 100%, 91.83% at 3 months, and 83.67% at 6 months, with a local recurrence rate of 16.33% (8/49). Palliative ablation group: The partial response (PR) rate at 1 month was 100%, decreased to 85.71% at 3 months, and further declined to 57.14% at 6 months. One patient in this group developed disease progression (PD) at 6 months. All patients showed improvement in quality of life, with ECOG scores decreasing from an average of 3.2±0.6 before surgery to 2.1±0.5 at 1 month and further improving to 1.3±0.4 at 6 months. Most patients were discharged within 3-5 days after the procedure, with a rapid recovery and no significant long-term decline in quality of life. Conclusion: CT-guided percutaneous liquid nitrogen cryoablation is a safe and effective minimally invasive treatment, especially for elderly lung cancer patients who cannot tolerate surgery. The technique has the advantages of less trauma, less pain, faster recovery, and significant short-term efficacy, especially in radical ablation with higher complete remission rate. Palliative ablation can effectively relieve symptoms and improve quality of life, but the long-term results may need to be further optimized in combination with other treatments. This study provides an important reference for the individualized treatment of elderly lung cancer patients and lays the foundation for the future application and development of cryoablation technology.