Abstract: Objective: To explore the feasibility and methods of reducing the tube current personalized based on the waistline in Multislice spiral CT examination of thoracolumbar trauma. Methods: the CT model of 55~120cm waistline was obtained from bovine lumbar segments. The vertebral body was scanned with 25~300mA and other scanning parameters were un-changed. The tube current value was obtained when the image quality was standard. First 131 non traumatic cases of lumbar CT examination were scanned for the normal and low dose conditions, and the suitable low dose scanning conditions were screened. 43 cases of thoracolumbar trauma centrums were scaned for the routine and screening low dose scanning. The images of faults and MPR and VR and MIP were comparatively analyzed. Results: the correlation between the current of CT scanning tube and the waist circumference is high; the correlation coefficient of Pearson is 0.994. The regression equations y=1.053x-33.187, R²=0.984 was derived with the tube current as argument and waistline as the dependent variable. The dose of low dose scanning was significantly lower than that of the conventional dose scanning; the image quality in the bone cortex, the spinal canal structure, the spinal canal soft tissue and the overall image quality (bone window and soft tissue window) was significantly different from that of the conventional dose group, but their scores were all good and acceptable; The good rate of VR and MIP reached 93%. Conclusion: the examination of thoracolumbar trauma on low-dose multislice spiral CT based on waistline is feasible. The images obtained and the quality of the post-processing images can meet the needs of clinical diagnosis and can be applied to the examination of thoracolumbar trauma.