Abstract: Taking the stem s and roots of tw o fu ll sib clones w ith significant d ifference in roo ting rate as testmaterials, tw o differential expression cDNA librar ies o f Larix cutting during root ing w ere established by PCR se lectTM cDNA subtract ion k i.t The resu lts of analysis of Rsa I d igest ion, ligat ion and subtraction eff iciency show edtha t the tw o libraries w ere established successfully. The posit ive clones w ere screened by PCR and dot blots. 521UniEST w ere obta ined by sequenc ing and b io informat ics ana lysis.