Methods and apparatuses for transmitting and acquiring system information and a communication system. The apparatus for transmitting system information includes: a first transmitting unit configured to transmit a paging message on a first bandwidth part (BWP), the paging message comprising indication information indicating a system information modification; and a second transmitting unit configured to transmit updated system information on a second BWP; wherein, the first BWP is different from the second BWP. Hence, the paging message and updated system information are transmitted on different BWPs, thereby saving signaling overhead of the system for transmitting the updated system information.