Aim To study the gene structures of apolipoproteins of Beijing duck insusceptible to atherosclerosis,the cDNA libraries of duck liver cells were quickly constructed at the first time.Methods With single-step method. total RNA was isolated frorn duck liver tissue. following purification of mRNA which Passed through oligo dT cellulose chromatography. Using mRNA as the template . the first and sceond strands of the cDNAs were synthesized in Time Saver cDNA synthesis Kit. After been ligated with EcoRl /Notl adaptors, the cDNAs were cloned into the arms of λgt10 or λgt11 vectors. Then the recombinants of ADNA were packed to infect E. coli Y 1090 strain. Results Duck liver cDNA libraries with high titer were obtained and rate of positive recombinants was over 98. 5 %. Autoradiography showed that sizes of cDNA products were in 400～ 5000 bp. Each clear plaque DNA which was identified by endorestriction enzyme digestion contained the cDNA insert. Full length cDNA sequence of duck apoAI was cloned and sequenced from the cDNA library constructed.Conclusion Compared with conventional method of constructing cDNA library the present one is simple,time-saving and eady to be used. Some problems of using the method to construct cDNA library were discussed in detail.