An image method for classifying insects includes the following steps: obtaining detecting images of the insects in a detecting area; obtaining a first foreground image related to the insects by background subtraction; extracting the saturation from the first foreground image and eliminating the non-characteristic objects therein to obtain a second foreground image; extracting the characteristics related to the insects from the second foreground image according to a threshold; and, determining the classifications or the sexes of the insects according to the characteristics. Accordingly, the image method for classifying insects can be used for automatically classifying the insects so as to save the manpower and time. |