The utility model relates to an acetylene safety device which comprises a cylinder, wherein the cylinder is filled with a liquid; a gas inlet pipe a comprises a plurality of parallel gas inlet ducts; one end of the gas inlet pipe is arranged outside the cylinder, and the other end extends to below the liquid level in the cylinder; a gas outlet pipe comprises a plurality of parallel gas outlet ducts; one end of the gas outlet pipe is arranged outside the cylinder, and the other end extends into the cylinder and is above the liquid level; and the outer wall of the cylinder is provided with a liquidometer. By utilizing the water insolubility of the acetylene, the acetylene safety device effectively prevents the acetylene from combustion and spreading, avoids endangering the acetylene generator, and avoids severe combustion explosion accidents.