Abstract: Using the lignite, screw extrusion and humus to completely replace the peat in the substrate formula, we obtain 7medium.Via compared experiment of formula breeding, the influence to physical and chemical property, sprouting rate, maturing seedling rate and seedling diathesis of different mixed scale of screw extrusion and liginite is studied .It is showed that, when the screw extrusion proportion exceed 50 percent and the liginite proportion is smaller than 10 percent, physical and chemical property will be changed sharply, sprouting rate slows downward tendency, order level reduced, sprouted time prolonged, and seedling diathesis changed badly. But when the screw extrusion proportion is smaller than 50 percent and the liginite proportion exceed than 10 percent, the situation is changed slightly, the proportion of screw extrusion and lignite have less influence to above aspects. The 2 processes which proportion of lignite and screw extrusion is separately 45 percent plus 30 percent and 35 percent and 40 percent are close to the ck, can basically meet the requirements of tobacco breeding medium. At last, the feasibility of this substituted medium is also confirmed by the study.