Abstract: In order to understand the molecular mechanism of the pesticide resistance of diamondback moth,Plutella xylostella,we used the SMART (switching mechanism at 5 end of RNA transcript) technology to construct full-length cDNA libraries.The PowerScript reverse transcriptase was used to synthesize and anchor the first-strand cDNA.Following reverse transcription,LD-PCR was performed using a modified oligo (dT) and an anchor primer to enrich the cDNA population for full-length sequences.The unamplified cDNA library contained 2.6×106 independent clones,in which the recombinant clones with an average insert size of 1.6 kb was > 96%.The titer of the amplified library was 2.4×1010 pfu/mL.PCR analysis of 60 randomly selected clones showed that 65% of cDNA clones contained inserts of above 1.0 kb.From the cDNA library,a full-length ribosomal protein L27A cDNA with 5 and 3 untranslated regions was isolated.