Abstract: Effects of exogenous cadmium on DNA cross-linking in leaves of potted corn were studied. Results showed that as the cadmium concentration increased, the extraction of DNA in leaves of super sweet corn CT38 decreased. 10 d after the treatment with cadmium, DNA extraction in the treatment of cadmium concentration in 1 and 100 mg/kg decreased 8% and 52% respectively, compared with CK in the same period. Cadmium reduced the extraction of DNA in corn leaves, and the longer the stress on DNA, the serious damage the plants suffered. With the increasing cadmium concentrations, corn DNA hyperchromic effect increased first then decreased. Electrophoresis bands of leaves DNA under cadmium stress dirfted to low-molecular-weight obviously. With the processing of 30 and 60 d, under cadmium concentrations in range of 5~100 mg/kg, DNA content of small molecule increased as the cadmium concentration increased.