Abstract:The chromosome spreading of metaphase kidney cells was conducted by colchicine-low concentration-air drying technique in Leuciscus merzbacheri,and Ag-NORs,C-band and G-band were analyzed in this paper.L.merzbacheri had a diploid chromosome number of 2n=50,its karyotype formula was 18m + 14sm + 6st + 12t,NF=82,and sex chromosome was not found.The Ag-NORs polymorphisms were individually specific,1-2 in number,and the frequency of single Ag-NORs was the lowest(10%),while the frequency of 2 Ag-NORs was the highest(70%).Ag-NORs mostly appeared in the chromosome m1 and m4.The associations of Ag-NORs were not observed.All the chromosomes were C-band positive,and composed of centromeric C-band and telocentric C-band.The G-bands in homologous chromosomes were basically coincident,and distinctive character of banding number and distribution could be identified in every homologous chromosome.