Plasma parameters such as the electron density and temperature play a key role in the dynamics of the solar atmosphere. These characteristics are important in solar physics because they can help us to understand the physics of the solar corona, the ultimate goal being the reconstruction of the electron density and temperature distributions in the solar corona. The relations between emission and plasma parameters in different timescales are studied. We present a physics-based model to reconstruct the density, temperature, and emission in the EUV band. This model, called COronal DEnsity and Temperature (CODET), is composed of a flux transport model, an extrapolation model, an emission model, and an optimization algorithm. The CODET model parameters were constrained by comparing the model’s output to the TIMED/SEE record instead of direct observations because it covers a longer time interval than the direct solar observations currently available. The most important results of the current work are the recovery of SSI variability in specific wavelengths in the EUV band, as well as the variations in density and temperature during large timescales through the solar atmosphere with the CODET model. The evolution of the electron density and temperature profiles through the solar corona in different layers during solar cycles 23 and 24 will be presented. The emission maps were obtained and they are in accordance with the observations. Additionally, the density and temperature maps are related to the variations of the magnetic field in different layers through the solar atmosphere.