The invention is applicable to the key technical field of million-kilowatt-class advanced pressurized water reactor nuclear power plants, and provides a cross-base nuclear power plant alarm linkage method and device. The method includes the steps: monitoring a plurality of bases in real time and judging whether an alarm linkage system of each base normally runs or not; realizing security and protection monitoring by the alarm linkage system of the current base if the alarm linkage system normally runs; judging the alarm grade of emergency alarm signals transmitted by the alarm linkage system of the current base by an emergency command center system if not; starting corresponding authority management according to the alarm grade; calling an execution plan according to the emergency alarm signals. The alarm signals are generated when illegal attacking happens, a command center extracts on-site alarm position information from the integrated alarm signals, an image acquisition device group is called to acquire on-site images, the on-site images are automatically popped up on a monitor, authenticity and severity of unexpected events are timely known, sound and light alarms are given, and the images automatically popped up in an alarm area are recorded.