In this study, Mn3O4 thin film was prepared by the chemical bath deposition (CBD) method on commercial microscope glass substrate deposited at 30 degrees C. The Mn3O4 film was annealed in an air atmosphere for an hour at temperatures 100 degrees C, 200 degrees C, 300 degrees C, 400 degrees C, 500 degrees C, respectively. The effect of annealing temperature on structural and optical properties such as optical constants of extinction coefficient (k), refractive index (n), the real (epsilon(1)) and imaginary (epsilon(2)) part of the dielectric constant and energy band gap (E-g) of the film were determined. The experimental characterization techniques included X-ray diffraction (XRD), UV-vis spectrophotometer and Hall effect measurement. XRD analysis showed that the film is grown in a polycrystalline structure in tetragonal phase. The conductivity of the film as a function of annealing temperature was measured as (1.32-6.65)x10(-6) (Omega cm)(-1).