The optical detection method which reflects the changes in the tumor cells growth process by researching on their spectra is obtained. According to the Beer-Lambert law,the changes of concentration of molecules such as aromatic amino acid and porphyrin in HeLa cells during the growth process of cell cycle will result in absorption spectra differences. Measuring the ultraviolet and visible absorption spectrum of the tumor cells can obtain the changes of spectrum during the different cell cycle growth phases. The relationship between cell cycle of tumor cells and characteristic peak of spectral curve can be acquired from the ultraviolet and visible absorption spectrum. The changes of intracellular specified molecules during the cell cycle of tumor cells can be detected by UV-visible spectral method. It provides new ideas for cell cycle studies.