We choose ROE is greater than 20% and analyze different Required Rate of Return whether they defeat Taiwan Stock Market Index to have different proportion. Eventually, to sum up, under different Required Rate of Return, we defeat Taiwan Stock Market to obtain almost same probability; thus we understand different Ks not to influence its outcome. I think it’s a good tool to buy stocks, because we select these stocks, they defeat Taiwan Stock Index over 60%; hence we prove investors choose high ROE and Required Rate of Return at the same time, and it’s will be a great benefit to the investors.