The total synthesis of three new prenylated flavanones, (2S)-5,7,2'-trihydroxy-8,3'-diprenylflavanone (I), (2S)-5,2'-dihydroxy-6'',6''-dimethylchromeno-(7,8:2,3'')-3'-prenylflavanone (II) and (2S)-5,7,2'- trihydroxy-5'-(1''',1'''-dimethylallyl)-8-prenyl flavanone (III) was first achieved through C-prenylation, protection of phenolic hydroxyl group, aldolcondensation, cyclization and deprotection starting from substituted benzaldehyde,2,4,6-trihdroxy aceto phenenone and o-hydroxybenzaldehyide,with total yield of 42%. All structures of new compounds were confirmed by IR, 1H NMR and LCMS.