Overview: Image edge extraction is a widely used and rapidly developing technology, playing an important role in medical imaging, enhanced vision, automatic driving and other fields. In recent years, there has been growing interest in developing miniature metasurface devices to obtain image edge information. Currently, it has been reported that discrete metasurface edge detection devices are used to obtain image edge information, but discrete metasurfaces often maintain a high energy efficiency only near the preset wavelength, and the energy efficiency decreases when deviating from the preset wavelength, which will limit the operating bandwidth of the metasurface optical computing device. Here, an optical differential device is designed by using a metasurface composed of quasi-continuous nanostrips to realize one-dimensional images edge detection. By changing the spatial orientation of quasi-continuous nanostrips, the device achieves geometric phase in the range of 0~2π, and maintains high energy efficiency over a wide wavelength range. The optical path system consists of two linear polarizers and two lenses with the same focal length, of which two lenses are placed in a confocal position to form a classical 4f optical system. The designed quasi-continuous metasurface edge detection device is placed on the Fourier plane of the 4f optical system. The original image is located on the object plane of the 4f optical system (at the front focal plane of the lens 1), and the object edge information is finally obtained on the image plane of the 4foptical system (at the rear focal plane of the lens 2). The simulation results show that the designed sample can achieve high average energy efficiency edge detection in the whole visible and near-infrared bands. Specifically, the quasi-continuous meta-device can obtain a clear image of object edge in the wavelength range of 400 nm~1000 nm, the energy efficiency of the device reaches 90.27% at the wavelength of 600 nm, and the average energy efficiency is 64.57% at the wavelength of 400 nm~1000 nm. Compared with the traditional edge detection devices based on discrete metasurface, the quasi-continuous devices have higher broadband average energy efficiency. Hopefully, this work enjoys many research merits in signal processing, optical communication and machine vision.In this paper, we design an optical differential device based on quasi-continuous metasurface and realize one-dimensional edge detection of an optical image. By changing the spatial orientation of quasi-continuous nanostrips, the device achieves geometric phase in the range of 0~2π, and maintains high energy efficiency over a wide wavelength range. The simulation results show that when the illumination wavelength increases from 400 nm to 1000 nm, the quasi-continuous meta-device can achieve clear images for the target edge. The maximum energy efficiency is 90.27% (the incident wavelength is 600 nm) and the average energy efficiency is 64.57% (the incident wavelength changes from 400 nm to 1000 nm). It can be expected that the proposed method can promote the application of quasi-continuous metasurface in image information processing and ultrafast optical computation.