In order to examine the pre-treatment effect of crab shell on Pb2+ removal by crab shell in aqueous solution, acid and alkali pre-treated crab shell were used. Electron microscopy techniques such as TEM (transmission electron microscopy) and SEM (scanning electron microscopy), and EDX (energy dispersive X-ray) and FTIR (Fourier transform infrared) spectrometry techniques were used to investigate the process of Pb2+ removal by acid and alkali pre-treated crab shell. The Pb2+ removal by acid pre-treated crab shell was much lower than that by untreated crab shell because of the decrease of CaCO3 from the crab shell. However, the Pb2+ removal by alkali pre-treated crab shell increased compared to that by untreated crab shell. The results were confirmed by TEM, SEM, EDX and FTIR.