The influence of additive Konjac Glucomannan (KGM) in a variety of con- centrations on the crystallization morphology and structure of calcium oxalate (CaOxa) has been investigated by infrared spectroscopy, scanning electron microscope, X-ray diffraction and so on. The results showed KGM can complex with the Ca2+ions; low concentration KGM prevents CaOxa from aggregating, raises the concentration of ions in the solution, reduces the quantity of crystals and inhibits their growth, and the crystals are round and blunt; while high concentration KGM promotes the growth of crystal, which appears in sheet-like or irregular shape. Only CaOxa monohydrate was observed in a certain system with or without the presence of KGM. The influence of additive Konjac Glucomannan (KGM) in a variety of con- centrations on the crystallization morphology and structure of calcium oxalate (CaOxa) has been investigated by infrared spectroscopy, scanning electron microscope, X-ray diffraction and so on. KGM prevents CaOxa from aggregating, raises the concentration of ions in the solution, reduces the quantity of crystals and inhibits their growth, and the crystals are round and blunt; while high concentration KGM promotes the growth of crystal, which appears in sheet-like or irregular shape. Only CaOxa monohydrate was observed in a certain system with or without the presence of KGM.