Over the past few years, Bitcoin is a hot topic for investment. Be more specific to talk about this topic, People speculate Bitcoin like gambling. It increases almost 10 times since few years ago. In my opinion, Bitcoin might be a new investment direction because it has edges in the currency system of the world. However, it will become a bad investment tool if there is a large-scale speculation in the investment market. On the other hand, the deal of cryptocurrency is the internet. In the internet, the biggest and largest risk is the privacy problem. The cryptocurrency system need to enhance and ensure the safety of the system. Otherwise, hackers can invade into the system and steal the invaluable digital currency. In conclusion, Bitcoin is a new investment topic. The concept of cryptocurrency is good. Behind the good idea, it involves a lot of risks, such as privacy and internet safety problem. When an investment tool becomes a speculation direction, it is very dangerous because cost of the investment is very high.