In this paper, a systematic examination of the influence of various experimental parameters on the morphology and size of CaCO 3 particles at room temperature in the presence of poly (sodium 4-styrene-sulfonate) (PSSS) is presented. The as-prepared products were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry-thermogravimetry (DSC-TG) and X-ray diffraction (XRD). The results show that the CaCO 3 concentration, the pH of the solution, the average molecular weight of polymer PSSS, and surfactant additives, turned out to be important parameters for the control of morphologies of CaCO 3 . In particular, the monodispersed and bidispersed spherical CaCO 3 particles can be easily obtained depending on the experimental conditions. This research may provide new insight into the facile preparation of monodispersed spherical CaCO 3 particles and the synthesis of other novel inorganic materials.