Objectives: This study was to investigate the anti-oxidation and anti-cancer activity of Chaga mushroom extract. Extraction condition optimization and beta-glucan analysis and anti-cancer activity tests were also done. Methods: Optimum extraction conditions for Chaga mushroom extract were at a temperature of $90^{circ}C$ and 2hrs with 10 times of water. Extraction yield and economics were best under these conditions. Results: Anti-oxidation activity was the highest with the fraction of 100,000 MWCO and $IC_{50}$ value was $13{mu}g/ml$ and this value was comparable to that of vitamin E, alpha-tocopherol. Among the fractions from various organic solvents, ethyl acetate fraction showed the highest anti-oxidation activity with $IC_{50}$ value of $7{mu}g/ml$. For anti-cancer activity, chloroform fraction showed little anti-cancer activity and ethyl acetate fraction showed the best anti-cancer activity with $IC_{50}$ $1.5{mu}g/ml$ for stomach cancer cells. Anti-cancer activities for different molecular weight fractions were the best in the fraction of molecular weight less than 100,000Da, and $IC_{50}$ values for stomach cancer cells and liver cancer cells were 1.7 and $1.4{mu}g/ml$, respectively. Conclusions: From these results, we can conclude that the extract of Chaga mushroom could be a good source for functional food and natural anti-cancer medicine.