The invention discloses a sediment particle analysis device based on digital image technology, which includes a collection box, an image acquisition unit, and a sediment particle analysis system; wherein the image collection unit is arranged in the collection box for collecting sediment samples. Image; the sediment particle analysis system includes an input module, an image preprocessing module, an image binarization module, an edge detection and contour extraction module, and a statistical output module. The invention also discloses a sediment particle analysis method based on digital image technology. The image of the sediment particle sample is collected by a camera, and then the image is preprocessed, binarized, and edge contour is extracted, and the projected area of each particle is calculated. According to the equivalent projected area, the particle size of each particle is obtained, and then a series of particle information is obtained, which realizes the rapid measurement of the characteristic parameters of sediment particles.