Choroidal neovascularization(CNV) refers to abnormal choroidal vessels that grow through the Bruch’s membrane to the bottom of retinal pigment epithelium (RPE) or retinal neurepithelium (RNE) layer, which is the pathological characterization of age-related macular degeneration (AMD) and pathological myopia (PM). Nowadays, optical coherence tomography (OCT) is an important imaging modality for observing CNV. This paper creatively proposes a convolutional neural network with differential amplification blocks (DACNN) to segment CNV in OCT images. There are two main contributions. (1) A differential amplification block (DAB) is proposed to extract the contrast information of foreground and background. (2) The DAB is integrated into the U-shaped convolutional neural network for CNV segmentation. The method proposed in this paper was verified on a dataset composed of 886 OCT B-scans. Compared with manual segmentation, the mean Dice similarity coefficient can reach 86.40%, outperforming some existing deep networks for segmentation.