Abstract: The effects of strong light radiation on chlorophyll protein complexes and some photosynthetic characteristics of spinach's chloroplasts were studied. The experimental results showed that, with the time of radiation, the quantity of CPa band that belongs to PSII core chlorophyll protein complex decreased obviously first, and then the quantities of the bands that belong seperately to oligomer and dimer of LHCII decreased in different levels, and finally, almost the, most proportion of chlorophyll protein complexest bands including that of PSI were decomposed. It also showed that, when the chlorophyll protein complexes had been changed not evident enough by light stress, the Fv/Fo ratio and DCIP photoreduction activity which represent PSII, activities had been decreased obviously.