The invention provides nine oligonucleotides with sequences of SEQ ID NO: 1-9 or their functional homologues or a composition comprising the same and a method for treating B cell neoplasm by using the oligonucleotides or their functional homologues or the composition comprising the oligonucleotides. The oligonucleotides induce the apoptosis of B cell neoplastic cells, up-regulate CD40 on B cell neoplastic cells and stimulate the production of IL-10 from B cell neoplastic cells.