A series of ultrathin TiOx (0-12 nm) seeded (Ba,Sr)TiO3 (BST) thin films have been prepared on Pt (111)/TiOx/SiO2/Si substrates by RF-magnetron sputtering. Experimental results show that an ultrathin TiOx layer acts as an initial template for the BST films in the first nucleation stage, resulting in a significant influence on crystalline orientation and electrical characteristics of the resultant BST films. Interestingly, highly (111) oriented BST film [alpha((111))similar to 97%] with 5-nm-thick TiOx seeding layer exhibits a shifted Curie temperature (T-c=275 K) and an enhanced tunability of 61.16% at 400 kV/cm, when compared with (001)-oriented BST without TiOx layer (T-c=250 K and tunability=50.05%).