Bioactivity in vivo of ceramic materials has been related to their surface micro-topography and may be estimated by means of simulated body fluid method in vitro. In order to investigate the effect of surface topographies of akermanite ceramics on bioactivity in vitro, akermanite ceramics were synthesized by sol-gel method and different surface topographies of disc-shaped akermanite ceramics were prepared by polishing with different SiC sandpapers. Atomic force microscopy (AFM) was used to evaluate the surface morphology and roughness. The bioactivity in vitro of ceramics with different surface states was evaluated by soaking the ceramics in simulated body fluid (SBF). And the samples after being soaked were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectrometry (EDS). The results showed that the amounts of precipitated apatite on the ceramics with different surface roughness after being soaked in SBF were different and the bioactivity in vitro of ceramic with rough surface was significantly higher than that of ceramic with smooth surface. The study suggested that suitable surface roughness may improve the bioactivity in vitro of akermanite ceramics. (C) 2010 Elsevier B.V. All rights reserved.