In this work, the high-quality 0.94(BiNa)TiO-0.06BaTiO (hereafter abbreviated as BNT-BT) lead-free piezoelectric thin films were synthesized by introducing LaNiO (hereafter abbreviated as LNO) seeding layers. The effects of LNO seeding layers on the crystal structure and electrical properties were systematically investigated. The X-ray diffraction patterns indicate that highly (100)-oriented BNT-BT films were prepared through utilizing LNO seeding layers. The maximum piezoelectric coefficient d of ~100 pm/V, remanent polarization 2P of ~18 μC/cm and dielectric constant E ~410 have been obtained in the highly (100)-oriented BNT-BT films. The observed tremendous enhancement of piezoresponse, ferroelectric and dielectric properties in LNO-seeded films can be attributed to the better crystallization quality, higher degree of (100)-preferred orientation and reduced leakage current density. These findings demonstrate that LNO-seeded BNT-BT thin films integrating with silicon substrates may provide a wide range of applications in high-performance MEMS devices.