Tricholoma matsutake Sing., with a variety of medicinal value such as antitumor, is one of the most popular edible mushrooms in the world.There have researched a lot on its polysaccharides which are considered as the main antitumor component.However, there have little literatures reports on other chemical constituents in its water extract which also have several bio-activities such as antioxidant.LC-MS is a very useful tool to identify compounds.We can get accurate molecular weight of the compounds by TOF-MS, while get affluent fragments information of the compounds by Trap-MSn.