An apparatus and method for converting a protocol interface are provided. A protocol converter may analyze a protocol of protocol data, and may sequentially output a plurality of sub-data of the input protocol data according to types of the plurality of sub-data and a plurality of phase information representing the types of the plurality of sub-data. A phase channel line may transmit phase information received from the protocol converter among the plurality of phase information. A data channel line may simultaneously transmit the received phase information and a sub-data corresponding to the received phase information.