The ITO films were deposited on glass substrates by RF-superimposed dc reactive magnetron sputtering and were annealed in $N_2$ vacuum furnace with temperatures in the range of $403K{sim}573K$ for 30 minutes. Electrical, optical and structural properties of ITO films were examined with varying annealing temperatures from 403 K to 573 K. The resistivity of as-deposited ITO films was $5.4{ imes}10^{-4}{Omega}cm$ at the sputter conditions of applied RF/DC power of 200/200 W, $O_{2}$ flow of 0.2 seem and Ar flow of 0.2 seem. As a result of annealing in the temperature range of $403K{sim}573K$, the crystallization occurred at 423 K that is lower than the crystallization temperature caused by a conventional sputtering method. And the resistivity decreased from $5.4{ imes}10^{-4}{Omega}cm;to;2.3{ imes}10^{-4}{Omega}cm$, the carrier concentration and mobility of ITO films increased from $4.9{ imes}10^{20}/cm^3;to;6.4{ imes}10^{20}/cm^3$, from $20.4cm^2/Vsec;to;41.0cm^2/Vsec$, respectively. The transmittance of ITO films in visible became higher than 90% when annealed in the temperature range of $423K{sim}573K$. High quality ITO thin films made by RF-superimposed dc reactive magnetron sputtering and annealing in $N_2$ vacuum furnace will be applied to transparent conductive oxides of the advanced flat panel display.