A system and a method for image searching. The method may include obtaining a target image and a plurality of images, wherein at least one similar image to the target image is to be searched from the plurality of images. The method may include determining a target feature vector of the target image and a feature vector of each of the plurality of images, each of the target feature vector and the feature vectors being an N-dimensional feature vector in an N-dimensional feature space. The method may include determining a search region in the N-dimensional feature space. The method may include determining one or more candidate images, the feature vector of each candidate image being within the search region. The method may further include determining the at least one similar image to the target image among the one or more candidate images.