A encoding/decoding method and device for a remote controller utilizing a baud rate to encrypt data for transmission. The encoding device includes an encoder encoding an identification code into an encrypted code; and an interpreter interpreting the un-encoded portion of the identification code and the encrypted code into a transmission signal. When the encrypted code is in a first base, the plain code corresponding to the encrypted code will be transmitted with a first baud rate; and when the encrypted code is in a second base, the plain code corresponding to the encrypted code will be transmitted with a second baud rate. The decoding device includes a receiver receiving the transmission signal; a interpreter connected to the receiver interpreting the transmission signal into a received signal; an encoder utilizing the same encoding algorithm as in the transmitter to generate a comparison code; and a processor comparing the received signal and the comparison code.