The invention discloses a method for implementing encryption and transmission of information and system thereof. The method comprises the following steps when a sender sends information to a receiver: a client of the sender encrypts the information by using a unique identifier of a receiver identity as a public key; the sender sends the encrypted information to the receiver; the receiver receives the encrypted information, and a client of the receiver performs decryption by using a user private key; wherein the client of the receiver obtains the user private key by one-off registration and the user private key matches with the unique identifier of the receiver identity. The system comprises an information transmission platform, a sender and a receiver connected to each other by the information transmission platform, clients provided in the sender and the receiver, and a registration component. According to the present invention, secure communication between the sender and the receiver is realized without a process of establishing any initial key, and the negotiation process between the sender and the receiver before encryption/decryption and the interactions with any other entities during every encryption/decryption procedure are avoided.