Cement-based composites were prepared from rice husk and styrene-acrylic emulsion (SAE) with semi-dry production process. The volume of SAE, the rice husk content and alkali treatment on the properties of the composites were studied. Particle-matrix bonding were observed with scanning electron microscope (SEM). The mechanical test of the rice-husk cement composites proved that SAE is an effective additive for reinforcing the composites, the mechanical properties improved significantly by alkali treatment and adding SAE. the properties can meet the requirement of the china building material standard(JC411—2007) when the content of SAE reached 3%.