Electronic Commerce increased rapidly according to the growing popularity of Internet. but payment system are not changed. Now main payment system of electronic commerce are credit card and cyber banking system. Then credit card has some problems safety, privacy etc, and cyber banking system has some problem also. We need new payment system to Electronic Commerce. The merit of electronic money are more capacity, more secure, more reliable, quick and easy to update, secure off-line processing, enabling technology etc than credit card and cyber banking system. And so many countries began using experiment of electronic money and our country began July KOEX building. But it has some problems (standardization, safety of payment, etc). Therefor we must make nile about electronic money in order to standardization and safety of payment. After then electronic money are used widely in electronic commerce.