The present disclosure relates to a pre-5th-Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4th-Generation (4G) communication system such as Long Term Evolution (LTE). A channel encoding method in a communication or broadcasting system includes identifying an input bit size, determining a block size (Z), determining an LDPC sequence for LDPC encoding, and performing the LDPC encoding based on the LDPC sequence and the block size.