MgO has been prepared by precipitation of magnesium nitrate solution with ammonium hydroxide,and the dechlorination abilities of the MgO for PP/PVC have been investigated.Moreover,effects of the MgO preparation conditions,including types of washing solutions and calcination atmosphere on dechlorination behaviors of PP/PVC have been discussed.Results prove that the obtained MgO(washing solution: ethanol;calcinations atmosphere: nitrogen) possesses much higher dechlorination ability than that of commercial grade MgO,which exhibits dechlorination degree of PP/PVC as high as 95.71wt.%.