Organic synthesis in the aqueous solution is a very active field. We synthesized amphiphilic ligands, which had phosphino alkyl group as a hydrophilic part and PEG as a lipophilic part. In the presence of the ligand and rhodium catalysts, hydroformylation of higher olefins in the aqueous solution proceeded to giving the corresponding aldehydes in good yields. The catalyst could be easily separated from products and recycled efficiently.