To shorten the time required for breeding new cultivars of Zea mays L., a better understanding of radiation mutagenesis by heavy ions is required to link initial DNA damage and assess how this varies with radiation quality. The dry seeds of Zheng 58 variety of maize were radiated by 7Li ion beams with 43MeV/u at doses of 0Gy, 10Gy, 20Gy, 30Gy, 40Gy and 50Gy. The mutagenic biological effects were analyzed from morphology to genomics by statistics and molecular biological technology including random amplified polymorphic DNA, SDS-PAGE electrophoresis assay and simple sequence repeats assay. The statistic results of morphology showed that germination and survival rates were inhibited. In the M1 generation, germination rate, plant height and ear height changed in the way of saddle curve as the dose increased. The results of molecular biology suggested that the biological effects were significant at 10Gy and 40Gy, and the relationship between genomic variation results and dose was also saddle curve. 7Li ion beams is expected to become an effective source for directed mutagenesis.