A digital broadcast transmission system and a signal processing method thereof offers improved receptability. The digital broadcast transmission system includes an error correction encoding unit for encoding an input signal according to a predetermined error correction method; a synchronous signal inserting unit for inserting a synchronous signal in the input signal after the error correction encoding; a first pilot inserting unit for inserting a first pilot signal in the input signal which contains the synchronous signal therein; a second pilot inserting unit for inserting a plurality of second pilot signals in the input signal which contains the first pilot signal therein; a pulse shaping filter for pulse shaping the input signal with the first and the second pilot signals according to a predetermined roll-off factor; and a radio frequency (RF) unit for transmitting the pulse-shaped input signal to a transmission channel band. By inserting a plurality of pilot signals in the transmitted data, problems associated with disappearance of only pilot signal due to poor channel environment can be overcome.