Abstract: As an effective means of ionospheric monitoring, The NeQuick G model and Global Navigation Satellite System, GNSS Constellation Observing System for Meteorology Ionosphere and Climate 2, COSMIC-2 occultation provides the electron density and total electron content of the ionosphere at any time and space, respectively, TEC model data and measured ionospheric profile data. The ionospheric analysis algorithm based on GNSS data can reconstruct the spatiotemporal distribution of the ionosphere at any time, especially during periods of ionospheric disturbances. However, the ionospheric tomography algorithm is also limited by uneven data coverage and low vertical inversion accuracy. This article improves the three-dimensional ionospheric tomography algorithm by integrating the NeQuick G model profile and COSMIC-2 profile observation data. COSMIC-2 data is also used as one of the inputs to the tomography algorithm to reconstruct the ionospheric electron density distribution during the ionospheric disturbance phase in China and surrounding areas on November 3 and 4, 2021. At the same time, the observation data of the ionosonde was used as real data to evaluate the peak electron density (NmF2) and peak height (hmF2) of the F2 layer in the tomography inversion. The experimental results show that the improved NmF2 chromatography results have a Root Mean Squared Error, The highest improvement percentage for RMSE is 48.96%; The RMSE improvement percentage of the improved hmF2 chromatography results is the highest at 72.43%.