Abstract: In an e-mail encryption/decryption method, an e-mail encryption process is executed at a sending end before sending an e-mailmessagetoareceivingend. The e-mail encryption process is includes providing an e-mail message having a header and text, requesting selection of at least one portion of the text and decision of a password set corresponding to the selected portion, and encrypting the selected portion into an encrypted text region to be decrypted using the password set before sending the e-mail message to the receiving end upon receipt of a sending request. The header, encrypted text region and non-selected text portion of the e-mail message are timely displayed when the receiving end receives the e-mail message. Thus, the sending end can select to encrypt an e-mail message in part to facilitate use.