The present disclosure provides an alarm method, which comprises: acquiring
signal coverage of a plurality of alternative communication cells; screening the plurality of alternative communication cells according to the
signal coverage to obtain a target communication
cell, at least part of the area in the
signal coverage of the target communication
cell being located within a preset alarm area; and sending a public
alarm message to a terminal within the target communication
cell. The present disclosure also provides an alarm
system, a
cell broadcast center device, a computer readable medium and a
computer program product to solve the problem that part of the terminals within the alarm area in the present disclosure have safety risks because they cannot receive the public
alarm message.