The Raman spectra of single blood platelets from human body are acquired by using Raman tweezers and the biochemical information of Raman spectra is extracted. The carotenoids concentration of platelets is found to be highest among the blood. But the carotenoids concentration of platelets is heterogeneous and is irrelevant to the content of lipids and protein of platelets. After platelets is activated, the Raman intensities of carotenoid are constant but those of proteins arise. The Raman intensity of carotenoids decreases but the relative intensities of lipids remain stable when platelets are stored at 25 ℃. The Raman intensities of lipids stored at 4 ℃ 12 d decline while those of carotenoids unchange.