This work reports the current-temperature characteristics of the low-temperature-sputtered (Ba0.8Sr0.2)TiO3 (BST) film post treated by rapid thermal annealing (RTA) in O2 ambient. The top electrode was biased under negative/positive voltage to investigate the interface properties of the Pt/BST/Pt multifilm. As the results, the current density of the RTA-treated BST film was greatly reduced owing to compensation of oxygen vacancies. The RTA-treated BST thin film biased at negative voltage exhibits a negative temperature-coefficient-resistivity (NTCR) behavior, but, intriguingly, that biased at positive voltage reveals a positive temperature-coefficient-resistivity (PTCR) behavior. According to the leakage current analysis, the Schottky emission dominates the negative biased current at upper interface, but the Heywang barrier scattering confines the positive biased current.