A warning system for barriers of highways comprises a plurality of barrier plates erected on two sides of roads in a different distance arrangement, and each including an optical fiber and a power line for network connection and communication connected therewith, and including a plurality of LED warning lights and LED illumination lights attached thereon; a number of electric control boxes affixed onto the barrier plates in a different distance arrangement, and each electrically connecting with the optical fiber and the power line for controllably changing warning and illuminating signs of the LED warning lights and the LED illumination lights; a plurality of solar energy devices matching with the electrical control boxes for absorbing and storing solar energy to supply power in the night or in electricity shortage; multiple monitor stations severing to monitor the electrical control boxes for controlling the LED warning lights of the barrier plates to change warning signs.