A mounting device for mounting a fan includes a base board and two blocks to be mounted on opposite sides of a bottom of the fan. The base board forms two rods. Each block defines a fixing hole in which a corresponding rod engages. A resilient member is mounted to a bottom of each block for absorbing vibrations of the fan. The resilient member includes an arc-shaped main piece, and two fixing pieces respectively extending from opposite ends of the main piece to be mounted to opposite ends of the corresponding block, respectively.