Abstract: Main nutritional and medicinal components of pileus and stem of log cultivated Reishi (G.lucidum) were analysed.The results showed that contents of protein,fat and amino acids of the stem were lower than the pileus,but polysaccaridae and triterpenois acids were 0.98% and 0.12 mg/g respectively.In addition,the ratio of essential amino acids was higher than the pileus.Therefore,the stem can be applied into the extract production.Experiment results showed that extract rates of stem,pileus of grade C and B were 2.03%～2.06%,3.64%～3.76% and 4.65%～4.85% respectively,and there were obvious differences among main components in their extracts or extract powders.The extract rate can be controlled within the ranges from 3.03% to 3.12% and 3.92% to 4.03%,while two suitable material compositions (pileus of grade B with 30% stem and pileus of grade C with 20% stem) were adopted and the product quality was relatively stable.Thereby,the product quality was effectively under the control.Our extract powder samples were analysed and checked in Japan,and were identified up to standard.The content of polysaccaridae was higher than the similar product in Japan.