One rapid and inexpensive spectrophotometric method was developed to screen rice embryos for lipoxygenase-3-null, based on the oxidative ability of 9-hydroperoxide, the catalytic product of lipoxygenase-3, combined with the specific inhibitor of lipoxygenase, namely nordihydroguaiaretic acid, when purified lipoxygenase-3 or the surface of cut rice single embryo was exposed to emulsions containing linoleate. The 9-hydroperoxides were detected by one color test based on the oxidation of iodide-starch. The optimal experimental conditions for above method had also been surveyed. Compared with the normal monoclonal antibodies method, this new method is more reliable, simple, costs less reagent, which could also be used as the useful tools for breeding storable rice.