Abstract:The karyotypes of four species of Dunaliella were analyzed using Giemsa staining method. The organisms were cultured in Ben-Amotz medium with 1.5 mol/L NaCl at 25℃ in a 12/12 h light-dark cycle for three days to induce synchronous growth of the algae. The karyotypes were observed after a series of treatments including pretreatment with 0.05% colchicine for 12-16 h, hypoosmotic shock, fixation, and dropping from 60 cm high to glass slide for breaking the surface coat of Dunaliella cells. All species observed are haploid with short and bacilliform chromosomes． The chromosome numbers of Dunaliella species are n=13 in D．salina，n=20 in D．primolecta， n=l0 D．bardawil，and n=l6 D．parva．All the chromosomes are wim median centromere, and the primary constrictions were obvious.