This data is China's "Class DMSP-OLS" 1km night light remote sensing dataset, and the available time series is from 1992 to 2021. The long time sequence night light remote sensing dataset covers Chinese Mainland. The processing method is to calibrate the DMSP-OLS data using the "pseudo invariant pixel" method, and consider the consistency of the time resolution of the DMSP-OLS data and the SNPP-VIIRS data, to repair the missing data in the original monthly SNPP-VIIRS data before synthesizing the annual SNPP-VIIRS data. In addition, the improved DMSP-OLS dataset (1992-2021) was calculated by further combining the calibrated DMSP-OLS data (1992-2013) and the Class DMSP-OLS data converted from SNPP-VIIRS data (2013-2021).