Portland cement has been restricted in applications to ecological area because of its environmental harmfulness and the $CO_2$ emission during a production process. Geopolymer materials attract some attention as an inorganic binder due to their superior mechanical and eco-friendly properties. In this study, geopolymer-based cement was prepared by using aluminosilicate minerals (flyash, meta-kaolin) with alkaline-activators and its compressive strength with concentration of alkaline-activators was investigated. Aluminosilicate-based geopolymers were obtained by mixing aluminosilicate minerals, alkaline solution (NaOH or KOH with different concentration) and water-glass under the vigorous stirring for 20 min. Compressive strength after curing at $30^{circ}C$ for 3 days increased with the concentration of alkaline-activator due to the enhanced polymerization of the aluminosilicate materials and dense microstructure. Aluminosilicate-based geopolymer cement using KOH as an alkaline-activator showed high compressive strength compared with NaOH activator. In addition, geopolymer cement using fly-ash as a raw material showed higher compressive strength than that of meta-kaolin.