The Nanjing University of Information Science and Technology (NUIST) Earth System Model version 3 (NESM v3) has been developed, aiming to provide a numerical modeling platform for cross-disciplinary earth system studies, project future Earth’s climate and environment changes, as well conduct subseasonal-to-seasonal prediction. In this report, I would like to share with you our experiences and lessons learnt during the model development in the past 5 years. I will describe the NESM v3 ‘s basic features and how the major improvements were made. I will also present model evaluations and demonstrate the v3 model’s fidelity and suitability to address the global climate variability and change issues. The pre-industrial (PI) experiment shows negligible trends in the net heat flux at the top of atmosphere and the Earth surface. The estimate radiative forcing of quadrupling carbon dioxide is about 7.24 Wm^-2, yielding a climate sensitivity feedback parameter of -0.98 Wm^-2K^-1, and the equilibrium climate sensitivity is 3.69 K. The transient climate response from the 1% yr^-1CO₂(1pctCO2)increasing experiment is 2.16 K. The model’s performance on internal modes and responses to external forcing during the historical period will be presented. Remaining issues will be discussed.