La0.85Sr0.15MnO3　(LSMO)/TiO2　heterostructures　are　synthesized　by　RF　magnetron　sputtering　with　different　LSMO　thicknesses.　The　rectifying　properties　of　the　junctions　are　related　to　the　LSMO　thickness　and　good　rectifying　properties　appear　in　the　LSMO　(100　nm)/TiO2　junction.　Furthermore,　an　excellent　rectifying　characteristic　is　presented　over　a　relatively　wide　temperature　range　for　LSMO　(100　nm)/TiO2　heterostructures.　All　samples　exhibit　a　huge　effective　resistance,　which　plays　an　important　role　in　the　I-V　curves　as　well　as　the　rectifying　properties.　The　diffusion　potential　of　the　heterostructures　decreases　as　the　measurement　temperature　increases,　which　is　attributed　to　the　modulation　of　the　interface　electronic　structure　of　LSMO/TiO2　heterostructures.　The　metal-insulator　(M-I)　transition　of　LSMO　also　appears　in　the　heterostructures　and　the　increased　sheet-resistance　of　heterostructures　at　low　temperature　is　related　to　the　introduction　of　effective　resistance.