LiNb $_{1-x}$ Tax O3 thin films were successfullydeposited on Pt(111)/Ti/SiO2/Si(100) substrates by spin coatingwith a diol-based sol-gel technology and rapid thermal annealing.The effects of various processing parameters, including Ta content(0 $\leq x\leq1$ ) and heating temperature (500 ~ 800 °C), onthe growth and properties of thin films were investigated. With theincrease of Ta content, the grain size of film decreased slightly,and the maximum f factor (the degree of c-axis orientation) ofthe films were obtained in the composition of x = 0.2. As thecomposition of film varied from x = 0 to x = 1, the relativedielectric constant of film increased from 33 up to 62, and thedielectric loss factor (tanδ) also increased from 0.00374 to0.00686, respectively. The coercive field, Ec, and remanentpolarization, Pr, decreased but pyroelectric coefficient, γ,increased from 2.76 × 10−8 up to 4.51 × 10−8 C/cm2 K. The pyroelectric figures of merit, Fv and Fm,indicated that film with Ta content of 20 mol% and heatingtemperature of 700 °C exhibited the optimized pyroelectriccharacteristics and could be applied for high-performancepyroelectric thin-film detectors.