Objective To investigate the risk factors of cognitive dysfunction in patients with traumatic brain injury. Methods From March to September, 2021, 556 hospitalized patients with traumatic brain injury were selected from a multicenter study. A 1∶1 sex-matched case-control study design was used. After assessment by Montreal Cognitive Assessment (MoCA), those with cognitive impairment were as case group and those without cognitive impairment were as control group. They were collected general data and assessed with Social Support Rating Scale (SSRS) and Hospital Anxiety and Depression Scale (HADS). Results Logistic regression analysis showed that college education or above (OR = 0.040) and high level of social support (OR = 0.118) were protective factors for cognitive impairment (P < 0.05). Aged 60 to 88 years (OR = 9.996), severe brain injury (OR = 7.345), headache after injury (OR = 2.159), frequent waking at night or multiple dreams ≥ three times per week (OR = 3.705), severe upper limb dysfunction caused by brain injury (OR = 6.072), depression (OR = 5.202) were risk factors for cognitive impairment (P < 0.05). Conclusion The related factors for cognitive impairment in patients with traumatic brain injury include general factors, disease factors, sleep, psychological and social support and other factors. It is suggested that in addition to the treatment of disease, it is necessary to improve sleep, psychology and social support, to reduce the incidence of cognitive impairment and promote the recovery of disease.