The invention discloses a method and a device for automatically positioning a binding hole of a document image. The device comprises a screenshot module, a gray scale conversion module, a filtering module, a positioning module, an abnormal circle processing module, and an exporting module. The screenshot module cuts a to-be-processed region. The gray scale conversion module performs gray scale conversion of the to-be-processed region. The filtering module denoises the gray-scale-converted image with Gauss filtering. The positioning module carries out Hough circle positioning processing on the denoised image. The abnormal circle processing module conducts abnormal circle processing on the positioned image. The exporting module exports circle center coordinates and radius data of a binding hole. The method and the device can automatically position a binding hole of a monochrome, gray or colored document no matter if the binding hole is a regular round hole or an irregular hole.