The usage of Tremella fuciformis heteropolysaccharide or T. fuciformis heteropolysaccharide extract in preparation of medicaments, food or functional food for promoting the growth and/or propagation of beneficial bacterium, in preparation of medicaments, food or functional food for ameliorating constipation, in preparation of medicaments, food or functional food of cosmetologic activity, and in preparation of accelerants for promoting the growth and/or propagation of beneficial bacterium in vitro.