Mn-Based thin film thermistors with a sandwich structure were prepared on Pt/TiO 2 /Ti/SiO 2 /Si substrates by a chemical solution deposition method and annealed at different temperatures (600, 650, 700 and 750°C). Effects of annealing temperature on microstructure and electrical properties of the prepared thin film thermistors were investigated in detail. The results showed that the degree of crystallization and grain size was enhanced; the resistivity and the aging coefficient were decreased with the increase of annealing temperature. The carrier concentrations were not affected by the annealing temperature. The thin film thermistor annealed at higher temperature has larger value of dielectric permittivity at low frequencies, while it has smaller value of dielectric permittivity at high frequencies than those thin film thermistor annealed at lower temperature.