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Surface UV-B irradiance can have a very important impact on the Earth"s ecosystem. In the modern industrialization process, human activities have led to significant changes in the atmospheric system, such as the reduction of stratospheric ozone, the emergence of ozone holes, tropospheric atmospheric composite pollution and other phenomena, and the corresponding changes in global surface UV-B irradiance, which have brought significant impacts on human and ecological environment, such as skin cancer and crop yield reduction. Therefore, it is important to monitor the surface UV-B irradiance. There are two main ways to monitor surface UV-B irradiance: ground-based monitoring and satellite monitoring. Ground-based platform surface UV-B irradiance monitoring has disadvantages such as sparse site distribution and short operation time. Compared with the limited ground-based monitoring, satellite remote sensing technology can realize the long-term monitoring of global surface UV-B irradiance, which is important for ecosystem assessment and atmospheric science research, etc. At present, there are few surface UV-B irradiance products based on domestic satellites, so the preliminary inversion of surface UV-B irradiance from environmental trace gas monitoring instrument(EMI) on the Gaofen-5 satellite is carried out in this paper. Firstly, a sensitivity analysis of the factors influencing surface UV-B irradiance was performed using the SCIATRAN model to reduce the time consumed in constructing the look-up table construction and interpolation look-up. Based on the results of sensitivity analysis of surface UV-B irradiance, the input parameter nodes of the clear-sky surface UV-B irradiance lookup table are reasonably determined, and the surface UV-B irradiance of EMI under clear-sky conditions is calculated. Then, the research on the correction methods in the presence of clouds and aerosol scenarios was carried out, and the correction of surface UV-B irradiance under clear sky conditions was realized by the cloud correction method based on Lambert equivalent reflectance and the aerosol correction method based on aerosol index to obtain the surface UV-B irradiance under actual conditions, and the inversion of global surface UV-B irradiance was completed. Finally, to verify the correctness of the EMI surface UV-B irradiance algorithm, the results of the algorithm were compared with the European OMI satellite data and WOUDC site data at the same time using a linear fitting method, where the correlation coefficient R with the OMI data was greater than 0.9, and the correlation coefficient R with the WOUDC site data reached more than 0.91, both of which indicate that the results of the method are in high agreement with the OMI data and WOUDC data. However, there are still some shortcomings. The surface UV-B irradiance inversion algorithm of EMI has high accuracy in the region with low surface albedo; while the results are large in the region with high surface albedo. The results show that surface UV-B irradiance products of EMI are highly accurate and can provide a research basis for subsequent releases of surface UV-B irradiance and other related products. These also demonstrate the payload"s capability in global surface UV radiation spatial and temporal distribution monitoring applications, providing a basis for long-term monitoring of the spatial and temporal variation of surface UV-B irradiance studies.