Abstract: The chiral ammonium salts have been used as phase transfer catalysts for asymmetric synthesis. The addition of chloroform to benzaldehyde in the presence of chiral ammonium salts, quinine, N-benzyl-quininium chloride (BQC), N-benzyl-dihydroquininium (BDHQC), N-(o-nitrobenzyl) quininium chloride (NBQC), N-benzylquinidinium chloride (BQDC), N-benzylcinchonium chloride (BCDC), N-dodecylquininium bromide (DQB), quinine-acrylonitride copolymer (QN-AN), N-benzyl quininium chloride-acrylonitride copolymer (QNBC-AN) and N-benzyl-N-methylephedrinium chloride (BMEC) is reported. The effects on the optical yields, such as (Ⅰ) the solvent effect (Ⅱ) the amount of catalysts (Ⅲ) the time of reaction and the Induction machanism are studied.