Abstract: In order to isolate target genes associated with disease resistance,two cDNA libraries viz.L45-72 and L69-72 were constructed on the basis of anti-disease cDNA fragments obtained by fluorescent DDRT-PCR with ready-to-use kits and pathogen-inoculated poplar leaves of I-69 and I-45,two clones either extremely resistant or susceptible to black spot disease in poplar.The library of I-45(L45-72) had a titer of 3.44×10~9 pfu/mL and the library of I-69(L69-72) had a titer of 3.94×10~9 pfu/mL,with inserts larger than 500 bp accounting for (96.67%) and 73.33%,respectively.The libraries constructed have laid a foundation for studies on the mechanism of disease resistance and disease susceptibility.