Flammulina velutipes is known as edible and medicinal mushroom. The fungus grow on living trees of Zelkova carpinifolia and dead trees of Diospyros lotus (Stand and fallen) in Behshar forest area. These plants were found as new hosts for F. velutipes. In vitro antagonistic activity of this mushroom against Bipolaris sorokiniana, Ophiostoma ulmi, Pestalotiopsis funerea, Fusarium culmurum, and Fusarium oxysporum was evaluated on MEA as dual culture. Colonies of the fungus were white farinaceous and powdery on MEA, later turns yellow. Daily growth of colony was measured 5.36mm on MEA at 25 o C. Growth coefficient was indicated 36.64 and 90 mm Petriplate was covered up to 15 days after plating. The strongest and poorest antagonistic index have been seen against Ophiostoma ulmi and Bipolaris sorokiniana, respectively.