The invention discloses a method for identifying a bubble image. The method comprises the following steps: firstly using known bubble contour samples to generate a bubble database; then acquiring bubble and suspension images of a to-be-tested water body, extracting bubble contours and suspension contours from the acquired bubble and suspension images, using a similarity comparing method to compare each extracted bubble contour and suspension contour with the bubble contour samples in the bubble database, selecting contours with a similarity greater than a set threshold value and determining the aforementioned contours as suspected bubble contours; then conducting gray scale statistics on each suspected bubble contour, determining that a suspected bubble contour having a gray value which gradually becomes small from a center thereof to an edge thereof is a bubble contour. According to the invention, the method can accurately separate bubble images from suspension images of the water body, acquires accurate bubble contours, so that the method provides helpful support to accurate computing of bubble particle sizes, addresses the problems of bubble volatility, difficulty in storage and identification.