The research on the technology of infrared absorption spectrum and its application plays an important role in the development of technology of optical measurement. The analysis technology of blood infrared absorption spectrum is presented in the present paper. By comparison between and analyzing the infrared absorption spectra of the normal blood sample and the high cholesterol blood sample, the differences were obtained. The infrared absorption spectra of normal blood serum and high cholesterol blood serum were detected, and the differences between the spectra are presented. The analysis results indicate that the differences of the absorptivity, the absorption peak position and the absorptivity ratio between the normal blood sample and the high cholesterol blood sample can be taken as a criterion to check the normal and abnormal blood sample. This work, valuable for application, provides an important reference for the diagnosis of diseases.