We present an observation-based elemental Galactic Cosmic Ray (GCR) heavy nuclei spectra model, based on ACE/CRIS measurements. Then we extrapolate the spectra model to the lower energy range of ACE/SIS instrument. In addition, we compare the modeling results with both the CRIS and SIS measurements. The flux of lower energetic particles measured by SIS are despiked since there are Solar Energetic Particle (SEP) events. The good agreement between the modeling and the observation results, especially for the solar minimum, indicates the validity of our model in the energy range 30 MeV/nuc–500 MeV/nuc. Compared with two GCR radiation environment models, CRÈME96/Nymmik model and Badhwar & O'Neill model, our model can provide an improved fit to the GCRs spectra measured by ACE. Furthermore, our model is a phenomenological one, without consideration of the physical process during GCRs' propagating through the heliosphere. Therefore, it is more straight-forward and applicable in practice. Finally, the model can reproduce and predict the GCR spectra in the past and future, respectively, based on the strong correlation between the model parameters and solar activity indicated by sunspot number.