The invention discloses a system and a method for encrypting short messages by using a mobile phone terminal. The system comprises a secret mail box management module arranged on a main board of the mobile phone, wherein the secret mail box management module comprises a password management sub-module used for setting, modifying, deleting and verifying short a message password of a user, an information-to-be-sent encryption sub-module used for encrypting the short messages edited by the user and a received information decryption sub-module used for decrypting the encrypted short messages received by the user. The system has the advantages of solving the problem of information content reveal existing in the communication process, realizing one-to-many secure communication, and having a function of sending the edited short messages at a scheduled time.