The invention discloses a while-drilling sound wave well cementation quality evaluation method and a processing device. The while-drilling sound wave well cementation quality evaluation method comprises the steps that 1, while-drilling data are pre-processed, and full-wave train data of array sound waves are obtained; 2, the influence of drill collar waves in the head waves is eliminated; 3, the energy of a head wave is calculated, and the wave energy of a sleeve in a window is calculated according to the length of the window; 4, a head wave array attenuation factor is calculated, and a corresponding array attenuation factor is calculated according to the obtained head wave energy; 5, a cementation index is calculated, and the cementation index is calculated by using a cementation index calculation formula according to a fitting formula of the attenuation factor of the block and the CBL; 6, the well cementation quality is comprehensively evaluated by using a cementation index curve; and 7, whether all the depth points are processed or not is judged, if so, processing is ended, and if not, the steps are repeated until all the depth points are processed. According to the while-drilling sound wave well cementation quality evaluation method, the problems of long time consumption and high cost during well cementation quality evaluation of highly-deviated wells and horizontal wells in cable logging can be solved.