The invention provides a regional fire alarm method. The method comprises the following steps: S01, calculating a trigger field of a certain single detector A in a building; s02, positioning a building structure infinitesimal element where the single detector A is located, and recognizing an adjacent detector; s03, selecting a building structure infinitesimal signal parameter unit where the singledetector A is located, obtaining detection signals of the detector and adjacent detectors of the detector, and obtaining signal characteristics through processing; s04, inputting the signal characteristics into a fire alarm model, and judging whether there is a fire; and S05, outputting a true alarm signal or a false alarm signal according to judgment. For different building structure infinitesimal elements, fire smoke spreading rules are different, and therefore the correlations of the adjacent smoke sensing signals are different. The correlation of the adjacent smoke sensing signals causedby the fire smoke spreading rule is used as a fire alarm judgment standard, then the standard is used for fire alarm, the false alarm rate can be reduced to a great extent, and the alarm efficiency isimproved.