LixTixNi1-2xO (x =0, 10 and 20 at. %) thin films with 200 nm in thickness were deposited on Pt/Ti/SiO2/Si (100) by a sol-gel spin-coating method. All samples have a uniform microstructure. The grain sizes grew from 100 nm to 300 nm by co-doping Li and Ti. The LiTiNiO thin films consist of NiO, NiTiO3 and Li2NiO2, while the Li-free thin films consist of NiO, NiTiO3 and NiTi0.99O3. The dielectric properties of the LiTiNiO thin films improved obviously by co-doping Li and Ti, but excess Li increases the amount of Li2NiO2 phase and decreases the dielectric properties. The dielectric constants at 100 Hz for the Li0.1Ti0.1Ni0.8O and Li0.2Ti0.2Ni0.6O thin films are 506 and 388 respectively. Appropriate co-doping contents of Li and Ti are important to obtain a high dielectric property.