A new Arabidopsis mutant eil,whose phenotype showed some lesions on leaves induced by high temperature, was found. The genetic analysis showed that the eil mutant was a homozygote of recessive single gene mutation. By analyzing the content of H 2O 2 and tissue staining of the wild-type and the mutant, we found that H 2O 2 had accumulated before the phenotype of mutant occurring. Lesions of the mutant on leaves did not occur under the high-temperature condition when the seedlings grew in culture medium with DPI (The inhibitor of NAD (P)H oxygen enzyme). The experiment showed that the function of Arabidopsis EIL gene was related to oxygen burst which leads to cell death. EIL is a gene conferring negatively controlled oxygen burst.