In this paper, we use the Raman spectra measured from platelet to the diagnosis of Alzheimer"s disease(AD). The Raman spectra used in the experiments were preprocessed with the following method and then fed into the classifier. The first step of the preprocessing is a simple smoothing followed by background elimination to the original spectra to make it easy to measure the intensity of the peaks. The last step of the preprocessing was peak alignment with the reference peak. After the inspection of the preprocessed spectra, we found that proportion of two peak intensity at 743 and 757 ㎝？¹ and peak intensity at 1658 ㎝？¹ are the most discriminative features. Then we apply mapstd method for normalization. The method returned data with means to 0 and deviation to 1. With these two features, the classification result involving 278 spectra showed about 95.5% true classification in case of MLP(multi-layer perceptron). It means that the Raman spectra measured from platelet would be effectively used to the diagnosis of Alzheimer"s disease.