Abstract: The characteristics of fly ash as a resources were studied. The theory of separating carbon from fly ash and utilizing them was presented. The equipment of separating carbon from fly ash through high voltage and static field was produced. Using “double mixed” technology of separated-carbon-fly-ash and decreasing aqua of highly effect and early strong, the renovation technologies of highway concrete pavement were studied. The separated-carbon-fly-ash can highly improve the property of concrete pavement. And the quantity of fly ash replacing cement reaches 20%. The main problems of utilizing fly ash directly on pavement engineering were solved preferably.