To explore value of hippocampal hydrogen proton magnetic resonance spectroscopy (1 H-MRS) in diagnosis and evaluation of cognitive impairment after traumatic brain injury (TBI). Methods: Nine patients with mild post-TBI cognitive impairment (mi-TBI group) and 19 patients with moderate post-TBI cognitive impairment (mo-TBI group) were enrolled. At the same time, 10 healthy subjects (control group) were recruited. The concentration of each metabolite in the bilateral hippocampus of the three groups were analyzed after 1H-MRS examination: N-acetylaspartic acid (NAA), choline (Cho), and creatine (Cr). Neurocognitive tests included the Mini Mental State Scale (MMSE) and Montreal Cognitive Function Assessment Scale (MoCA), and the differences in cognitive function scores and metabolite ratio among the three groups were compared. Correlation analysis on the above data results was performed. Results: The NAA/Cr and NAA/(Cho+Cr) ratio of the bilateral hippocampus of the patient groups were lower than those of the control group (P<0.05). The Cho/ Cr ratio of the right hippocampus of the patient groups was higher than that of the control group (P<0.05). The Cho/Cr ratio of the left hippocampus showed no significant difference between the groups (P>0.05). The MMSE and MoCA scores of the two patient groups were lower than those of the control group (P<0.05). The MMSE and MoCA scores in the mi-TBI group were positively correlated with the NAA/Cr ratio of the bilateral hippocampus (P<0.05) and had no significant correlation with the Cho/Cr ratio of the left hippocampus (P> 0.05), but the scores showed a negative correlation with the Cho/Cr ratio of the right hippocampus (P<0.05) and a positive correlation with the NAA/(Cho + Cr) ratio of the bilateral hippocampus (P<0.05). The MMSE and MoCA scores in the mo-TBI group were positively correlated with the NAA/Cr ratio of the left hippocampus (P< 0.05), negatively correlated with the NAA/Cr ratio of the right hippocampus (P<0.05), and had no significant correlation with the Cho/Cr ratio of the bilateral hippocampus (P>0.05); however, compared with that of the control group, the Cho/Cr ratio tended to increase and was positively correlated with bilateral hippocampal NAA/(Cho+Cr) ratio (P<0.05). Conclusion: 1 H-MRS combined with neurocognitive tests can help to diagnose cognitive dysfunction more objectively and accurately after TBI.