The invention discloses a guardrail cleaning vehicle which comprises a second-class chassis truck. A water tank, a water pump, a second engine, a hydraulic station and a rinsing mechanism are arranged on girders of the chassis truck. A supporting wheel mechanism is arranged on one side of the girders of the chassis truck. The second engine provides power for the hydraulic station and the water pump. The rinsing mechanism comprises a bottom frame, a first supporting beam, a second supporting beam, a first support, a second support, a first oil cylinder, a second oil cylinder and a third oil cylinder, and a plurality of rolling brushes driven by oil motors are correspondingly mounted on the first support and the second support. The first oil cylinder can drive the first support to move up and down, the second oil cylinder can drive the second supporting frame and the second support to move relative to the first support, and the third oil cylinder can drive the first support to rotate. Two first rails perpendicular to the girders are fixedly arranged on the girders of the chassis truck, and a driving mechanism for driving the bottom frame to move along the two first rails is mounted between the bottom frame and the first rails. The guardrail cleaning vehicle can adapt to isolating guardrails with different heights and widths, can conduct automatic cleaning at multiple angles, and is reliable in operation and high in cleaning efficiency.