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Objective:To discuss the initial applied research of traumatic fracture in long bones of impuberal pigs with low dose CT scanning, to seek and establish the best proposal of low radiation dose CT scanning.Methods:12 healthy and fresh hind leg exvivo of a pig were struck by means of blunt force, in order to produce fracture models.Then these were scanned with different imaging conditions in two multi-slice CT(MSCT), including Philips Brilliance 6 and Philips Brilliance 64. The various scanning parameters were as follows:①6-MSCT:tube voltages were 120kv, 90kv and tube current-time products were 200mAs 150mAs, 100mAs, 50mAs, 25mAs. Kv and mAs were combined in every two parameters and generated 10 groups of imaging conditions.②64-MSCT: tube voltages were 120kv, 80kv. Tube current-time products and the way of combination between Kv and mAs were the same as that of 6-MSCT. All CT images were assessed visually by two independent observers for image quality and fracture conditions using a 5-point scale (1-5)and interobserver concordance test was carried out. The rate of qualification of CT images quality was calculated. The noise level of CT images was demonstrated by standard deviation (SD) of CT value, which was measured by means of setting region of interest (ROI).Fracture conditions were compared between X-ray radiographs and CT images. CTDIv and DLP were recorded inevery scanning and effective dose (ED) was calculated. Statistical analysis was performed with Kruskal-Wallis Test for image scores among 10 groups of imaging conditions inevery CT modality and ANOVA among SD and CTDIv.