Traditional email business uses the plain text to transfer the mail content. If the eavesdropper captures the data packets and owns enough computing capability, he will easily analyze the data. Therefore the data might be leaked. Although there are some solutions that could increase the security performance of email, the insecurity factors still remain. To solve the above problem, a quantum mail transfer system is proposed to transfer the main data based on quantum channel. Combining quantum channel with traditional channel and establishing quantum SMTP protocol, POP3 protocol in email transportation process insure email security. The simulation analysis showed that the exposed probability of quantum email is closer to 0 when the length of mail data is near to 30 bit. So, even if the eavesdropper owns enough computing, the quantum mail transfer system owns better secure performance.