A simplified CaO-V₂O₅-MnO₂ system was established to qualitatively and quantitatively investigate the transformation behavior of vanadates. The results demonstrated dynamic transformations between calcium vanadate and manganese vanadate as n(CaO)/n(V₂O₅)/n(MnO₂) ratios and roasting temperatures varied. When MnO₂ was incrementally added with n(CaO)/n(V₂O₅) of 2, some Ca₂V₂O₇ converted to Mn₂V₂O₇. The mass of vanadium as calcium vanadate consistently exceeded that as manganese vanadate. Conversely, when CaO was gradually added with n(MnO₂)/n(V₂O₅) of 2, Mn₂V₂O₇ tended to transform into Ca₂V₂O₇ and Ca₃V₂O₈. The affinity of vanadium for calcium was higher compared that of vanadium for manganese. The specific type of calcium vanadate formed depended on both n(CaO)/n(V₂O₅)/n(MnO₂) values and roasting temperatures, while manganese vanadate remained predominantly as Mn₂V₂O₇. The influence of roasting temperature on the conversion between calcium vanadate and manganese vanadate was minimal. At n(CaO)/n(V₂O₅)/n(MnO₂) of 2/1/2 and temperatures ranging from 650 to 850 °C, the mass ratio of vanadium present as calcium vanadate to manganese vanadate stabilized at approximately 2.