A method for transmitting System Information (SI) includes that: a base station sequentially sends first to Xth SI according to scheduling periods and repeat times of the first to Xth SI in preset N pieces of SI (101), wherein N is a positive integer larger than 1, X is a positive integer larger than 1 and smaller than or equal to N, and the scheduling period and repeat times of the first SI are preset; and the base station notifies the scheduling periods and repeat times of the second to Xth SI through fields in the first SI (102). A base station, terminal and system for implementing the abovementioned method are also provided.