The invention discloses an infrared warning roadblock, which comprises a main body and a traffic lamp. A left roadblock body and a right roadblock body are arranged on the main body; the left roadblock body is mounted on the left side of the main body, and an infrared transmitter is arranged on the upper part in the left roadblock body; the right roadblock body is mounted on the right side of themain body, and an infrared receiver, an alarm and a controller are arranged on the right roadblock body; the infrared receiver is mounted on the upper part in the right roadblock body and is horizontally opposite to the infrared transmitter; the alarm is mounted at the top of the right roadblock body; the controller is mounted on the lower part in the right roadblock body and electrically connected with the infrared transmitter, the infrared receiver and the alarm; and the traffic lamp is arranged above the main body through a supporting rod and electrically connected with the controller. Pedestrians can be effectively reminded to stop walking forwards when a red lamp is on, thus safety of the pedestrians is guaranteed, and the traffic order is maintained.