0bjective To study the effects of Diisobutyl Phthalate (DiBP) on the behavior of male mice in spatial learning and memory. Method Seventy two Kunming mice were randomly divided into six groups (12 mice in each group), including Solvent control group, Positive control group (Scopolamine Hydrobromide) and four DiBP-treated groups. The mice in control group and positive control group were given corn oil by gavages. The mice in DiBP-treated groups were given DiBP in corn oil by gavages at the dosage of 50, 250, 500 and 1000mg/kg bw respectively for 8 weeks. Morris water maze and open field tests were conducted at the beginning and by the end of the experiment. Mice in positive control group were injected with scopolamine hydrobromide (5mg/kg bw) intraperitoneally before the last test. Results No significant difference in learning and memory ability of each group was observed at the beginning of the experiment. By the end of 8-week experiment, the time of staying in the center of open field was longer in the positive control group and 1000mg/kg bw DiBP-treated group than that in solvent control group ( P < 0. 05) in the open field test. The latent time of finding a hidden platform on the first day of training was significantly increased in the positive control group and the 500mg/kg bw and 1000mg/kg DiBP-treated groups in comparison with the solvent control group (P < 0. 01) in the water maze test. Conclusion The spatial learning and memory ability of male KM mice could be decreased on exposure to DiBP under the condition of this experiment.