Abstract: Taking the testis of male adults of Cyrtotrachelus buqueti Guer as the experimental materials, the chromosome number and morphology of C. buqueti were observed by acetic acid magenta tabletting method, and the karyotype characteristics were analyzed in this study. The results showed that the chromosome number of C. buqueti was 2n = 22, including 10 pairs of autosomes and 1 pair of sex chromosomes, all of which were centromeres of middle/sub middle, NF = 22. The sex determination mechanism of C. buqueti was Xyp type, and the karyotype formula was 2n = 22 = 16m + 4sm + Xyp. The percentage of chromosome with the longest chromosome to the shortest chromosome ratio greater than 4∶1, and the percentage of chromosome with the arm ratio greater than 2∶1 was 0.1. So the karyotype of C. buqueti was 2C type, and no secondary constriction and satellite characteristics were observed. The results supplemented the blank of the basic research on the classification characteristics of C. buqueti chromosome.