Objective: To analyze the relationships between clinical parameters and number of circulating tumor cells (CTCs) isolated from glioma patients and explore their possible clinical applications in early detection and prognosis prediction of glioblastoma patients. Methods: A total of 47 patients hospitalized in the Department of Neurosurgery of The First Affiliated Hospital of Nanjing Medical University from October 2018 to September 2022 were enrolled. All patients were clinically diagnosed with glioma. CTCBIOPSY? system was utilized for CTCs isolation and counting both pre-operatively and post-operatively, after which hematological test results, radiology images and follow-up results were collected and analyzed to explore the possible relationships among parameters. Results: CTCs were detected in 87.2% (41/47) of patients pre-operatively. GBM patients showed significantly higher CTC level than non-GBM patients(P=0.020). The combination of pre-operative CTC level and neutrophil to lymphocyte ratio could aid the diagnosis of GBM. A decrease in post-operative CTC levels was observed in GBM patients and the changes were of statistical significance compared with non-GBM patients(P=0.004).GBM patients were further divided into two groups designated high-CTC and low-CTC based on a cutoff value of pre-operative CTC ≥11/5ml peripheral blood. Statistical significance was observed in white cell count(P=0.017), neutrophil count(P=0.031), and lymphocyte count(P=0.018), but not in radiology features. Follow-up data of GBM patients showed significantly shortened overall survival in GBM-H patients than GBM-L patients (P=0.017). Conclusion: Pre-operative CTC counting readily distinguishes GBM from non-GBM patients and predicts adverse prognosis in GBM patients with higher pre-operative CTCs. It is a feasible candidate marker to aid the diagnosis and prognosis prediction of GBM.