Abstract: To explore the application of multi-source observation data in hail monitoring and warning,the conventional sounding data,satellite meteorological data,dual polarization radar data,wind profile radar data,and ground-based GPS water vapor data were used to study a strong convective weather process in central Hebei on June 25,2020.It was found that the effect of the north China cold vortex produced a suitable circulation conditions for the emergence of severe convection.Strong convection weather occurred and developed rapidly under the action of the ground convergence line and topographic uplift.A super monomer with extended life cycle was the main mechanism triggering this large-scale hail. Dual polarization radar was capable of distinguishing between hail and other phase particles since hail was plainly distinct from other phase particles.The quantitative fusion analysis of multi-source observation data can provide more accurate data information,so as to provide more reference value for the monitoring and early warning of hail weather.