The effect of attapulgite clay on the decolorization effect and the quality of oil was studied. On the basis of single factor test, the orthogonal test was used to optimize the technological conditions. The results showed that the effects of the three main factors on the decolorization in order were as follows: decolorization time >the amount of activated carbon>the dosage of decolorant. The optimal conditions were as follows: pre-decolorization 15 min, decolorization 15 min, 1.0% of spent clay, 2.0%of attapulgite clay and 0.1% of ac...