By comparing the differences between the data of Daxing sounding station, the nearest to Jizhou, Tianjing, and ECMWF (European Centre for Medium-Range Weather Forecasts) Reanalysis v5 (ERA5) data, the applicability of the ERA5-derived strong convection index under complex terrain conditions of Jizhou is validated and evaluated. The results are listed below. (1) The geopotential height, air temperature, and wind speed detected by Daxing sounding station are consistent with the corresponding ERA5 in the troposphere, which indicates that ERA5 can represent the meteorological characteristics above Jizhou, and it performs better at low altitude than at high altitude, but has poor performance on atmospheric humidity. (2) The convection indexes based on ERA5, such as CAPE (convective available potential energy), K index, SI (Showalter index), and PW (precipitable water), are all closely related with strong convective weather, and the correlation coefficients between them and the corresponding parameters of Daxing sounding station are 0.66, 0.90, 0.93, and 0.99, respectively, indicating that these indexes can reveal the stratification instability conditions. (3) The variation of the convection indexes constructed by ERA5 corresponds with the precipitation process in Jizhou, and ERA5 can reflect the change of weather and provide reference for analyzing strong convective potential.