Land economic coefficient is an important corrective coeffcient in farmland classification. With Yushan County cited for case study, theories and methods of Geostatistics was applied to explore calculation motheds of land economic coefficient. Semivariance of data of the soil samples from the country was analyzed. Results indicated that spatial correlation existed between land economic coefficients. To calculate economic coefficient of each land unit, the Kriging method was adopted. Results of sampling verification indicated that it is feasible to use the Kriging method in calculating land economic coefficients, which opens up a train of thoughts for determining land economic coefficients in classification of farmland.