Abstract: The calculation of doublet earthquakes early warning is still an unresolved issue in the worldwide, The situation of double earthquakes is complex and different double earthquake events have great differences. In April 2023, doublet earthquakes occurred in different places of Xinyuan County, Xinjiang Province. The Fujian earthquake early warning system responded quickly and released three early warning reports. The first early warning report was released 1.83 s after the first station was triggered, using data from 6 stations. Compared to the official earthquake catalog, the deviation of the epicenter position is 131.54 km and the magnitude deviation is 3.4. We find that different earthquakes may be associated into the same earthquake by associating the time sequence and spatial position triggered by the station. The judgment error of the first station of the early warning causes a large deviation in the calculation of the earthquake location and magnitude calculation. The processing algorithm of the two earthquakes in the early warning system needs to be improved and perfected. The range of earthquake influence can be determined by the attenuation of peak acceleration and the judgement for reasonableness of the first station can be determined by the triggering ratio of station around the first station, so as to improve and perfect the off-site double-earthquake processing algorithm of the Fujian early warning system.