Objective To investigate the characteristics and clinical significance of middle cerebral artery (MCA) atherosclerotic plaques in patients with acute cerebral infarction (ACI) as detected by computed tomography angiography (CTA).Methods The 102 patients with acute cerebral infarction (ACI) admitted to Wuxi Ninth People’s Hospital from August 2019 to August 2022 were selected as the ACI group, and 100 non-ACI patients with MCA atherosclerotic plaque formation in the hospital during the same period were selected as the control group. The degree of MCA stenosis and plaque characteristics of the two groups were compared, and they were stratified and further analyzed according to the severity of neurological impairment in ACI patients.Results A total of 104 cases of soft plaques (42.80%), 81 mixed plaques (33.33%), 34 fibrous plaques (13.99%), and 24 calcified plaques (9.88%) were detected in the ACI group, while there were 54 cases of soft plaques (24.88%), 32 mixed plaques (14.75%), 71 fibrous plaques (32.72%), and 60 calcified plaques (27.65%) in the control group, which were significantly different from those in the ACI group (P < 0.05). The degree of MCA stenosis in the ACI group was higher than that in the control group (P < 0.05). Among ACI patients with NIHSS scores no less than 15, there were 43 cases of soft plaques (44.79%), 40 mixed plaques (41.67%), 8 fibrous plaques (8.33%), and 5 calcified plaques (5.21%), whereas 61 cases of soft plaques (41.50%), 41 mixed plaques (27.89%), 26 fibrous plaques (17.69%) and 19 calcified plaques (12.93%) were detected in ACI patients with NIHSS scores less than 15. The compositions of the types of plaques were different among the two subgroups (P < 0.05). The degree of MCA stenosis in ACI patients with NIHSS scores no less than 15 was higher than that in those with NIHSS scores less than 15 (P < 0.05).Conclusions The MCA plaques in ACI patients are mainly mixed and soft plaques with moderate to severe stenosis, and are closely related to the degree of neurological impairment in ACI patients.