An effect of high-energy ball milling on the mechano-chemical conversion of celestite to strontium carbonate (SrCO3) was studied. A celestite ore was ground by a planetary ball mill in a highly concentrated sodium carbonate (Na2CO3) solution. The experimental study was carried out to determine the effects of milling time (15, 30, and 45 min) and Na2CO3 concentration (1, 1.25, and 1.5 M) on the particle size and SrCO3 percentage of the product. A celestite/ball weight ratio was selected as 1/10 and the volume of carbonate solution was calculated for the stoichiometric amount of sulfate in celestite, as constant. After filtering, washing and drying the precipitated SrCO3 sludge was analyzed by XRD, SEM-EDS. Powders were leached in HCl solution and analyzed by AAS in order to determine the SrCO3 amount in the product. A response surface methodology was applied via the Box-Behnken method for the results of particle size and SrCO3 percentage. Regression model coefficients were 98.61 and 98.14%, which were the results of compatibility as experimentally obtained and predicted by the model, respectively. The maximum amount of SrCO3, 96.84% and the minimum particle size, 10.297 mu m were obtained with the maximum values of the parameters, 45 min, 1.5 M Na2CO3, and 450 rpm.