The invention provides a warning fence with an acousto-optic alarming function. The warning fence comprises at least one common fence column. At least one equipment platform is installed on the common fence column, and the equipment platform is provided with an alarming, light and power supply system. The alarming, light and power supply system comprises an infrared alarm device, a warning light device and a power supply device, wherein the infrared alarm device is provided with a universal rotation pedestal which is capable of flexibly adjusting a detection angle and ensuring that no detection dead angles exist among the common fence columns, and is used for monitoring the pedestrian status within an alarming, light and power supply system domain outwardly extending from the range of the fence and giving an alarm when an irrelevant person approaches; the warning light device is mainly composed of a yellow LED stroboscopic warning lamp whose flash frequency is 90/min and is used for prompting passing cars to avoid a construction section as early as possible; and the power supply device is connected with the infrared alarm device and the warning light device for providing long-acting power. The warning fence with the acousto-optic alarming function is convenient to carry, long in usage time and obvious in alarming affect.