Objective To compare and quantitatively analyse the different characteristics of multimodal imaging of geographic atrophy (GA) in age-related macular degeneration (AMD). Methods The study included multimodel images of 32 eyes of 27 patients with GA secondary to AMD. There were 14 males (17 eyes) and 13 females (15 eyes). The age ranged from 64 to 83 years, with the mean age of (74.4±7.6) years. All eyes were examined by color fundus photography (CFP), fundus autofluorescence (FAF), fundus fluorescein angiography (FFA) and spectral domain optical coherence tomography (OCT). Using image J software, two trained ophthalmologists, operating in masked fashion, graded the area of lesions of CFP, FAF and FFA independently and compared the sizes of GA area. OCT was performed to confirm the border of lesion when FAF difficult to be determined. The results consistency of two ophthalmologists was analyzed by Bland-Altman. Results The results consistency was high of two ophthalmologists, with the variation range of FFA＜FAF＜CFP. The GA area of CFP, FAF and FFA were (19.81±13.03), (21.50±13.61), (23.10±14.29) mm2. The difference of GA area between three multimodel images was statistically significant (F=0.466, P=0.629). Conclusion The mean size of GA measured by CFP, FAF and FFA showed no statistical difference.