The present invention relates to method for producing construction aggregate, comprising the steps of: (i) preparing materials, which comprises (% by weight): fly ash (80 to 99.75%); alkaline activator (0.25 to 20%); water (6 to 30% of total weight of fly ash and alkaline activator); (ii) mixing the alkaline activator with all the aforementioned water amount to create alkaline activator solution, after which will be mixed with fly ash to create geopolymer mortar; (iii) molding the geopolymer mortar with the compressive force of 2 MPa and more with desired dimension, wherein the molding is carried out with hydraulic pressing, extrusion, rolling or tablet lamination. (iv) solidifying; and (v) optionally, crushing the construction aggregate obtained above to a predefined dimension. Besides, the present invention relates to the construction aggregate from fly ash obtained by the above mentioned method.