The effects of the electro-deposition conditions on the crystal structure and the properties of electrolytic manganese dioxide(EMD) were investigated in this paper. The results show that EMD was γ-crystal, with sand-like rough interface. The optimal preparation conditions of EMD were 30 min deposition time, and p H=1.0 in Mn SO4-H2SO4 solution at 50 ?C. Surfactant(P1) was conducive to the uniform and stable surface of γ-Mn O2 film, the impedance and the specific surface area of the electrode modified with γ-Mn O2 increased by 21.4 times and 75.6 times, respectively. The redox reversibility and the resolution ratio of characteristic peaks with the modified electrode were significantly improved in the benzodiazepines electrochemical reaction. The achievement illustrated that the controllable synthesis of γ-Mn O2 film thickness was practical in electrochemical sensors, and the determination reliability of benzodiazepines was improved with γ-Mn O2 modified electrodes used in environment monitoring technology. The effects of the electro-deposition conditions on the crystal structure and the properties of electrolytic manganese dioxide (EMD) were investigated in this paper. The results show that EMD was γ-crystal, with sand-like rough interface. The optimal preparation conditions of EMD were 30 min deposition time, and p H = 1.0 in Mn SO4-H2SO4 solution at 50 ° C. Surfactant (P1) was conducive to the uniform and stable surface of γ-Mn O2 film, the impedance and the specific surface area of the electrode modified with γ-Mn O2 increased by 21.4 times and 75.6 times, respectively. The redox reversibility and the resolution ratio of characteristic peaks with the modified electrode were significantly improved in the benzodiazepines electrochemical reaction. -Mn O2 film thickness was practical in electrochemical sensors, and the determination reliability of benzodiazepines was improved with γ-Mn O2 modified electrodes used in environme nt monitoring technology.