Based on the study of fertilization and deep ploughing in seed orchard of Chinese fir in Guanzhuang Forest Farm, Fujian Province. According to mathematics statistical inference, we can regard the regression equation between soil nutrient and the yield of cones as a model to forecast the output of cones in seed orchard. As a result, the standard of soil nutrient, with which the highest yield of cones would be produced, is set up. We have got to determine the nutrient contents in the soil in other Chinese fir seed orchard and contrast the nutrient with the criterion. We, then, know how much nutrient and what kind of nutrient to be needed in the soil. So an adequate fertilization can be applied in seed orchard. Above-mentioned is called the fertilization model in seed orchard of Chinese fir.