A user equipment, an earthquake alert server and an earthquake alert method thereof are provided. The earthquake alert server divides a map into a plurality of geographic grids and receives earthquake reporting messages from a plurality of user equipments. The earthquake alert server monitors the number of reporting messages of each geographic grid within a time interval to determine candidate earthquake grids, and determines earthquake grids according to the adjacent relationship among the candidate earthquake grids. The earthquake alert server chooses any two of the earthquake grids to classify the earthquake grids into two groups and increases a far value of each earthquake grid in the group whose reporting time is later. After multiple choices, the earthquake alert server labels the earthquake grid having the smallest far value as the epicenter grid and transmits an earthquake alert message to a plurality of remote equipments accordingly.