We conducted a pot experiment of rice planting with a complex soil polluted with heavy metals (Pb, Cd, Zn) and arsenic (As) to study the effects of the addition of calcium carbonate (CaCO₃) on the contents of exchangeable heavy metals and arsenic in soil, on the agronomic features and biomass of rice plants, and on the contents of heavy metals and arsenic in different organs of rice plants such as roots, leaves, hulls and seeds. In addition, we studied the relationships between amount of CaCO₃ and soil pH values, soil exchangeable contents of heavy metals and arsenic, and concentrations of heavy metals and arsenic in different organs of rice plants. The results showed that soil pH values increased with increasing amounts of CaCO₃, and were significantly related to the amount of CaCO₃. The exchangeable heavy metal and arsenic content in the soils decreased significantly after the addition of CaCO₃. Compared with the control group, the exchangeable Pb, Cd, Zn and As content decreased by up to 98.35%, 93.72%, 98.52% and 69.48%, respectively. The addition of CaCO₃ had no significant impact on the dry weight of rice roots, seeds and total biomass of the rice plants. Rice tiller weight and dry weights of stems and leaves decreased significantly at high CaCO₃ levels, indicating that excessive CaCO₃ addition might, to some extent, result in negative effects on rice growth. After the addition of CaCO₃, the heavy metal and arsenic content in different organs of the rice plants showed a declining trend compared with that of the controls. The distribution of Pb, Cd, Zn and As in various organs of the rice plants varied; the amount of Pb, Cd and As in rice roots was significantly higher than that in the other organs. When the CaCO₃ addition was greater than 1.0 g/kg, the Pb, Cd and Zn content of brown rice decreased by 62.68%, 40.2% and 34.95%, respectively. Meanwhile, the total arsenic content in different organs of the rice plants declined slightly, and the inorganic arsenic content reduced by 18.33%, but these decreases were not significant. Therefore, the biological effectiveness of arsenic was not effectively reduced by CaCO₃ in this study. The Pb, Cd and inorganic As content in the brown rice was still higher than that stipulated in the national standard GB 2762-2012, Maximum Levels of Contaminants in Food (Fruit). The addition of CaCO₃ reduced the biological effectiveness of Pb, Cd and Zn, resulting in decreases in Pb, Cd and Zn content in the rice roots, but and did not effectively prevent the leaching of Pb and Cd from the roots of brown rice. The exchangeable arsenic content in the soils decreased significantly by adding CaCO₃. However, the arsenic content in different rice organs did not significantly decrease, indicating that the biological effectiveness of arsenic did not significantly decrease in the soils.