Abstract: Magnesium oxide (MgO) was prepared by using polyvinyl alcohol (PVA) as template and the resulting MgO was then used as adsorbent in Methylene Blue (MB) adsorption. The effect of pH, temperature, the kinetic of adsorption and adsorption isotherm were investigated. The Mg (NO3)2.6H2O and PVA were dissolved, then mixed these solution together. An aqueous ammonia (NH4OH) was precipitant. The precipitate was washed, filtrated, dried and calcined to obtain MgO. The MB uptake over MgO showed clearly that at lower pH, the higher adsorption capacity was occurred. This might be because the surface of MgO produced more -OH group. In term of temperature, at higher temperature could induce more MB adsorption since the higher mass transfer. Moreover, the adsorption is an endothermic process and the order of adsorption process was suggested to be Pseudo-second order. The experimental data was fitted with Freundlich and Langmuir equation, the more linearity relationship was shown in Freundlich model. Therefore, the Freundlich isotherm was fitted better than Langmuir isotherm.