We have evaluated the ferroelectric and electrical properties of pure BiFeO3 (BFO) and (Bi0.9Ho0.1)(Fe1−xNix)O3−δ (BHFNxO, x = 0.01, 0.02, and 0.03) thin films as frequency varying from 1 to 50 kHz on Pt(111)/Ti/SiO2/Si(100) substrates by using a chemical solution deposition method. With the frequency from 1 to 10 kHz, the decrease of remnant polarization (2P r ) of the BHFN0.02O thin film was about 27 %, from 26 to 19 μC/cm2, which is one half lower than those of the BHFNxO (x = 0.01 and 0.03) thin films. Otherwise, the variation of the coercive electric field (2E c ) was relatively small, which were 16, 11 and 3 % for the BHFNxO (x = 0.01, 0.02, and 0.03) thin films. The remnant polarization (2P r ) and the coercive electric field (2E c ) values of the BHFN0.02O thin film show the dependence of measurement frequency and it has been fairly saturated about 30 kHz. Also, the leakage current density of the co-doped BHFN0.02O thin film showed three orders lower than that of the pure BFO, 2.14 × 10−6 Å/cm2 at 100 kV/cm.