Abstract: The sample data acquired in the process of geological exploration often deviate from normal distribution. So, the calculating values from relevant variogram will deviate from their real values. Analysing the distribution characteristics of ore-forming elements in samples, a method of calculating variogram by robust estimation is proposed to study the spatial ore-forming variability. Samples are available to obey normal distribution through exponential transform, then the variogram is calculated separately by median and tri-mean methods of robust estimation. The model optimization of variogram is verified according to crass-validation, and the result shows that the estimated value can get higher accuracy by means of robust estimation to calculate variogram.