Objective:To investigate the application value of KARL iterative algorithm combined with low-dose CT scanning in young and middle-aged patients with femoral neck fractures.Methods:The clinical data of 132 young and middle-aged patients with femoral neck fractures diagnosed by clinical and CT scan in Taizhou Bo′ai Hospital from August 2019 to May 2022 were collected. There were 68 cases in the conventional dose group reconstructed by projection, and 64 cases in the low dose group reconstructed by KARL iterative algorithm. The subjective image quality score, the excellent and good rates and CT value, signal to noise ratio (SNR) were compared between the two groups. The effective dose (ED), CT dose index (CTDIvol), dose-length product (DLP) were compared between the two groups.Results:There were no significant differences in subjective image quality score, the excellent and good rates between the two groups ( P>0.05). There were no significant differences in CT values and SNR of the trabecular dense area at the central level of the femoral head, the iliopsoas muscle at the same level, and the anterior abdominal wall or buttocks subcutaneous fat at the same level between the two groups ( P>0.05). The levels of CTDIvol, DLP and ED in he low-dose group were lower than those in the conventional dose group: (3.35 ± 1.05) mGy vs. (12.90 ± 2.92) mGy, (66.33 ± 20.26) mGy/cm vs. (253.12 ± 58.57) mGy/cm, (0.99 ± 0.30) mSv vs. (3.79 ± 0.88) mSv, there were statistical differences ( P<0.05). Conclusions:Based on KARL iterative algorithm combined with low-dose CT scanning has no significant effect on the clinical diagnosis and classification of femoral neck fractures, the scanning image has a high objective evaluation value, and can effectively reduce the radiation dose received by patients, which is useful for clinical preoperative diagnosis and surgical planning.