In order to solve the problems of weak edges, uneven illumination, and non-uniform bubble distribution in floatation surface bubble image, we propose a floatation bubble delineation method by combining nonsubsampled Shearlet transform (NSST) and multiscale boundary detection and fusion. First, we use NSST to decompose a bubble image into a low-frequency and multiscale multi-directional high-frequency subband images. Then, we use adaptive fractional order differential valley detection templates to extract valley boundary of the low-frequency subband, detect the edge information of high-frequency subband images based on scale correlation coefficient and direction modulus maximum, and extract boundary detail from the edge information by ridge characteristics determination. Finally, we implement bubble delineation through multiscale boundary fusion and morphological processing. Experimental results show that, the proposed method is affected little by noise and illumination, and can effectively delineate bubbles with different distribution types. The average detection efficiency and accuracy are much better than those of existing methods. This method meets the dynamic changes of flotation working condition well.