Abstract: The diploid chromosome number, karyotype, and DNA content were studied in metaphase chromosome in kidney cells and blood of blue common carp Cyprinus carpio blue var injected with PHA and colchicin by airdrying technique. It was found that the diploid chromosome number was 2n=100. The karyotype was found to be composed of 30 m, 26sm and 44st＋t chromosomes, and NF=156. The diploid nucleus DNA content was measured from the somatic cell of the blue common carp using flow cytometer （Beckman cellLab Quant, made in USA） and the DNA content （2.3 pg· N^＋） in erythrocytes of chick （Gallus sp） as standard. The common carp had DNA content of3.99pg·N^-1, corresponding to the result measured chromosome number as ploidy.

Key words: Cyprinus carpio blue vat, chromosome, karyotype analysis, DNA content