Metakaolinite (MK)-based geopolymer-polyvinyl alcohol (PVA) composite (GPC) was synthesized in the presence of aqueous phosphoric acid as an activator at room temperature. The microstructure and morphological changes of GPC were analyzed by means of X-ray diffraction (XRD), Fourier transform-infrared spectrometry (FT-IR), thermal analysis (DSC-TG), and scanning electron microscopy (SEM). XRD and SEM results showed that the amorphous phase, including C, O, Si, and Al elements, was probably present during the geopolymerization of MK powders. It suggested that geopolymer-organic polymer composite had been formed. FT-IR showed the absorption bands of MK were split and moved towards the lower frequency field. Thermal analysis results revealed that the transformational temperature of MK phase disappeared while the decomposition temperature of PVA in the GPC increased. In comparison with MK-based geopolymer, the compressive strength of GPC was obviously improved.