Abstract: Density of cavity, its burying depth and water proof method to cavity bottom are the three key factors of technique of cavity making by explosion in farm land. After a brief introduction of the method and economic analysis on the technique, in accordance with the theory of experimental method and taking wheat yields as target, the relationship between the three factors and wheat yield was studied in this paper. The results showed that water proof method to cavity bottom is the most important factor, the burying depth is the second, and the density of cavity is the third. This conclusion will lead to further study and technical popularization and application.