Crude glycerol can be obtained by distillation of biodiesel by-product. Its decoloration process by absorption of active carbon prepared by coconut shell was investigated and analyzed. The results indicated that LY-725B active carbon was selected as the optimal decolorant. In addition, decoloration temperature, decoloration time and active carbon dosage were chosen as the three main factors of response surface optimization model. After experiment and analysis with Minitab Program, the optimal process conditions were found as follows: m(activated carbon): m(crude glycerol)=2.2%, decoloration temperature 48℃ and decoloration time 31min. Under those optimal conditions, the transmittance and once through yield of discolored glycerol reached 96.1%, and 72.6%, respectively.