Abstract: Trichothecium roseum, the fungus causing postharvest-disease of fruits and vegetables, was used as the objective to investigate the effects of Lactobacillus plantarum CY1-2 at different concentrations（ 0, 1.0×101, 1.0×102,1.0×103, 1.0×104, 1.0×105, 1.0×106, 1.0×107CFU/mL） on the mycelia growth and conidia germination of T. roseum and decay of tomato fruit inoculated with T. roseum. The results showed that all different concentrations of L. plantarum CY1-2 could significantly depress the mycelia growth and conidia germination of T. roseum and restrain the lesion diameter of inoculated tomato fruit. The treatment with L. plantarum CY1-2 at 1.0×105CFU/mL increased relative conductivity, the content of soluble sugar and soluble protein in the T. roseum medium, whereas had no significant effect on malondialdehyde content. Which recommended that the mechanism by which the growth of T. roseum was suppressed by L. plantarum CY1-2 may be associated with the destruction of cell membrane.