AIM: To explore the value of frequency threshold optical coherence tomography(OCT)in the diagnosis of primary open angle glaucoma optic nerve injury. METHODS: Eighty patients with early primary glaucoma who were admitted to the hospital between January 2018 and March 2020 and 100 healthy subjects were selected as the study subjects. Patients with primary open angle glaucoma were divided into early group, middle group and late group. OCT was used to measure the thicknesses of upper, lower, nasal, bitemporal peri-papillary retinal nerve fiber layer(pRNFL)and upper and lower macular ganglion cell complex(mGCC)in each group. The mean deviation(MD)of visual field was determined through perimetry. The OCT parameters and perimetry parameters were compared among groups. Spearman correlation analysis was performed to analyze the correlation between OCT parameters and visual field defects, and the receiver operating characteristic(ROC)curve was used to calculate the value of OCT parameters in diagnosing primary open angle glaucoma. RESULTS: There were 24 cases, 39 cases and 17 cases in the early group, middle group and late group, respectively. There were statistically significant differences in pRNFL and mGCC among 3 groups(P<0.05).The upper, lower, average pRNEL and the upper, lower, and average mGCC of patients in the early group of a third-class hospital were significantly lower than those of the control group, and the parameters of pRNFL and mGCC in each position of the mid-stage and late group were significantly lower than those of the control group. The upper, lower, nasal pRNFL, average pRNFL, upper, lower and average mGCC of the late group of glaucoma patients were significantly lower than those of the early group and the middle group. The indicators of the middle group were significantly lower than those of the early group(P<0.05). Spearman correlation analysis showed that pRNFL and mGCC parameters were negatively correlated with glaucoma severity(P<0.05)ROC curve analysis showed that the areas under the curves of the upper, lower, nasal, bitamporal and average pRNFL for diagnosis of primary open angle glaucoma optic nerve injury were 0.693, 0.846, 0.676, 0.579 and 0.844, respectively. The areas under the curves of upper, lower and average mGCC for diagnosis of primary open angle glaucoma optic nerve injury were 0.542, 0.677 and 0.676 respectively. The area under the curve of average pRNFL combined with average mGCC for the diagnosis of primary open angle glaucoma optic nerve injury was 0.883. CONCLUSION:The pRNFL and mGCC measured by OCT are closely related to the degree of primary open angle glaucoma optic nerve injury. Both have high diagnostic value for glaucoma and can be used clinically for diagnosis and condition assessment.