This study presents some comments on paper "Classification of solar radiation zones and general models for estimating the daily global solar radiation on horizontal surfaces in China", [Energy Conversion and Management, 2017.10.043.] proposed by Liu et al. (2017). In their paper, the selected 4 models were studied before by Almorox and Hontoria (2004) in Spain and they did not present all discussion of their results which indicated that the cubic model gave a slight improve rather than the quadratic and linear models. The proposed general global solar radiation model is not new, it was developed and evaluated before by Rensheng et al. (2006).