Fourier Transform Infrared (FT-IR) spectrum is an effective method of investigating substance molecular structure swiftly while keeping the specimens intact, so it can represent the characteristic of the cancer at molecular level. Then all the differences of spectra between cancerous tissues and normal tissues are determined with FT-IR spectroscopy and analyzed with statistics of Logistic regression, the results show the pattern can be distinguished to lung cancerous tissues from normal tissues, and it is feasible to apply FT-IR spectroscopy in clinical practice.