AIM:To evaluate the effect of different cover methods in treatment of amblyopia with pattern visual evoked potential (P-VEP). METHODS:A prospective study was conducted with 136 monocularamblyopia children, aged 3-6 years old, selected from children optometry specialist out-patient. They were divided into covered group(69 cases) and partially covered group(67 cases), respectively. On the basis of accurate refractive correction, the healthy eye from each group was covered for 10, 5 hours per day, and at the same time, the same amount of fine eyesight training was conducted, respectively. P-VEP (P100 amplitude and potential) test results and visual acuity improvement were analyzed. RESULTS:One month after treatment, compared with before treatment, P100 amplitude increased and latency was shortened in full cover group, and the difference was statistically significant (P<0.05), while those differences in the partially covered group were not statistically significant (P>0.05), while the difference between the two groups was statistically significant; 6 months after treatment, the visual acuity increment: cure rate, progress rate and total efficiency rate between the two groups was statistically significant(P<0.05), the difference of the P100 amplitude, latency shortening in covered group was statistically significant compared with before treatment (P <0.05), and the differences between the two groups were not statistically significant(P >0.05); the visual acuity increment: cure rate, progress rate and total efficiency rate between the two groups was not statistically significant(P >0.05). CONCLUSION:The P100 amplitude and latency were improved in cover group after amblyopia treatment in early period, partially covered group had no obvious changes than before treatment, there were significant changes in visual acuity increment in the two groups, indicating that cover group has better efficacy than the partially covered group. In the long term, no significant difference was found between the P100 amplitude, latency and visual acuity, which further indicate that the long-term efficacy of the two methods is the same and regular PVEP test can evaluate the therapeutic effect and provide guide for further treatment.