To confirm the effects of the high wilting and the air exclusion from silo, Bahia grass (Paspalum notatum) containing 55 percent moisture was ensiled in the two miniature experimental silos. The one was kept in vacuo at almost 0 cm Hg after ensiling, for 189 days, the normal pressure being restored after 27 days, while the other was kept under the normal condition for 205 days as a control. The results obtained are summarized as follows: l) The air exclusion from the silo gave the silage a good effect without any surface spoilage. The analyses of this vacuum-sealed silage were: dry matter 46.9, crude protein 4.9, lactic acid 1.85, acetic acid 0.28 and butyric acid 0 percent. 2) A good silage was made certainly only with the high wilted grass, though a considerable surface spoilage was observed. The high wilting had the effective control over undesirable fermentation. The control silage contained dry matter 46.3, crude protein 4.2, lactic acid 2.32, acetic acid 0.35 and butyric acid 0 percent. 3) The conservation of pro-vitamin A was improved by means of the air exclusion from the silo; 80.6 and 52.7％ pro-vitamin A remained in the vacuum sealed and the control silage, respectively. 4 ) Furthermore, two normal HCl or 10％ sodium propionate solution was sprayed at the rate of 2.5％, since the development of mold on resulted silage after opening was undesirable. The retardation of apparent mold development was 1 day in the HCl-and 4 days in the Na-propionate-lot respectively. It was confirmed that both wilting or lowering moisture content of grass and the air exclusion from tile silo were practically significant for the good silage making.