Equations of State (EoSs) have been widely used in calculating solubility of solutes in supercritical carbon dioxide (SCCO2). However, the traditional EoS models, need the data of sublimation vapor pressure and critical parameter of solutes, which are difficult to obtain, and the calculation procedure is also complicated. In this study, simplifications and approximations were made towards combinations of three EoSs (Soave-Redlich-Kwong, Peng-Robinson, and modified Esmaeilzadeh-Roshanfekr) and five mixing rules (Huron-Vidal, van der Waals one and two, modified covolume-dependent, and Wong-Sandler) to overcome the above limitations. After simplifications and approximations, the modified models have been reduced into two groups, including two and three parameter models. At last, the models in the work of Yazdizadeh et al. (2012) and four semi-empirical models (Chrastil, Valle and Aguilera, Sung and Shim, and Sparks) were used for comparison, and comparative analysis suggests that the new models in this work are better. (C) 2016 Elsevier B.V. All rights reserved.