An algorithm of Stepwise Discriminant Analysis is used in the classification of Plasmodium blood smear. 9 features of the red cell is extracted. 169 red cells (among them 130 cells are normal, 39 contain Plasmodium) are used as training set, 192 red cells (among them 157 cells are normal, 35 contain Plasmodium) as test set. We have done the statistical analyses and got good results. For test set, the false negative rate is 11.4％, the false positive rate is 7.6％.