A prediction method for changes of physical parameters after earthquakes includes: obtaining a precipitable water vapor after an earthquake in a target monitoring area during a historical period; verifying the accuracy of the precipitable water vapor collected in the historical period; obtaining thermal anomaly data of the land surface temperature after the earthquake in the target monitoring area during the historical period; determining a time difference between peak of the precipitable water vapor and peak of the thermal anomaly of the land surface temperature; when the earthquake occurs again in the target monitoring area, detecting a time point corresponding to the peak of the thermal anomaly of the land surface temperature in the target monitoring area, adding the time point to the time difference to obtain a predicted time point of the peak of precipitable water vapor, and outputting the predicted time point as a time point of secondary disaster.