A mounting device for mounting a fan having two opposite boards includes a base board and two fixing members. The base board forms two rods. Each fixing member includes a connecting portion and two tabs perpendicularly extending up from the connecting portion. The connecting portion defines a fixing hole in which a corresponding rod engages. Four fasteners respectively extend through the tabs and then engage in the opposite boards of the fan, to fix the fixing members to the boards of the fan, respectively. A resilient member is mounted to a bottom of each fixing member for absorbing vibrations of the fan.