Objective: To investigate the effect of different volumes of isotonic washing solution (0.9% NaCl) on the quality of intraoperative autologous blood salvage in craniocerebral surgery. Methods: Thirty patients who underwent neurosurgical procedures with intraoperative salvaged blood volumes exceeding 800 mL between August 2022 and July 2024 were enrolled as study subjects. The salvaged blood was divided into four groups: group A, group B, group C, and group D. Group A was washed with 500 mL of isotonic solution (blood-to-washing solution ratio of 1∶2), group B with 1000 mL (ratio of 1∶4), and group C with 1 500 mL (ratio of 1∶6). After centrifugation, the washed blood was stored in designated blood bags (A, B, and C, respectively). Blood gas analysis was performed on 5 mL samples obtained from the centrifuged blood in groups A, B, and C, and from the unwashed blood in the reservoir of the control group (group D). Parameters including red blood cell (RBC) count, pH, hemoglobin (Hb), hematocrit (HCT), potassium ion (K ), sodium ion (Na ), and lactate levels were also measured using these samples. Additionally, blood samples from each group were examined microscopically to assess red blood cell morphology. Results: No significant differences were observed among groups A, B, and C in terms of RBC recovery rate, HCT, Na concentration, or lactate clearance rate (P>0.05). All three groups exhibited a reduction in pH, with group C showing a more pronounced decrease compared to groups A and B. Similarly, K clearance was achieved in all groups, with group C demonstrating superior efficiency. Microscopic analysis revealed a reduction in spiculated red blood cells across all groups, with group C achieving the highest clearance rate. Conclusion: Group C (washed with 1 500 mL solution) demonstrated optimal performance in reducing pH levels, clearing K , and removing spherocytes, while maintaining red blood cell recovery rate. Additionally, it did not significantly increase the risk of hypernatremia in critically ill neurosurgical patients, making it more suitable for craniocerebral surgeries.