The purpose of this study is to investigate online stock investment behavior in China. Online stock trading in China has been continuously growing since the Internet users in China have been dramatically increasing. Online stock trading investors can be classified into three groups and those are only Internet users, both Internet and offline branch users, and telephone users.To accomplish the purpose, literature survey was made on online investment behaviour and a conceptual model was built to determine significant factors. And some hypotheses were made to describe online stock investment behaviors in China. Some samples were collected from the Chinese investors. The comparative analysis between internet-based stock investors and off-line stock investors was made and many factors were shown the difference between two groups. Second, I used ANOVA analysis to determine important factors for internet-based stock investors and the effects of transaction cost to investor's investment frequency. The following factors were turned out to be important: financial management specialty, stock trade motive, and information use specialty.The results of hypotheses testing is as follows. First, there are lots of on-line stock trade, as the investors have more cash and real estate properties. Second, high satisfaction on fee payment is making more and more online stock trading. Finally, investors who are preferring online stock investment with low trading fees are investing lots of money with trading more frequently and using home trading.This study suggests that Internet-based stock investors are mostly young, highly-educated men, which can be an important basis of marketing data. And Internet-based stock investment is becoming more and more activated, including many investors in their early twenties in China. It means that many Internet-based stock investors don't possess their houses and it implies that the people are paying attention to personal financial management. Since most of them received university education on financial program they have enough knowledges to invest on online stock investment.Online stock trading has many advantages which are trading convenience on information use and low brokerage fee. But these are not always benefiting to all investors. Online trading will make investors indulged on stock market and so they can not concentrate on their works. Therefore. there will be a strong need for providing not only appropriate investment education systems but also personal financial and asset management for long-term investment. Also, the government has to take actions on educating the young generation so that they can be stock specialists or financial planners.