Thickness is a very important parameter to control the microstructures, as well as physical properties in the multiferroic BiFeO3 thin films. In this article, BiFeO3 thin films with different thickness (from 210 to 830 nm) are fabricated by chemical solution deposition on the Pt/Ti/SiO2/Si (100) substrates to investigate the thickness effects systematically. The results show that the crystallization is improved, the dielectric constant is enhanced, and the leakage current is reduced with increasing thickness. On the other hand, the magnetization and magnetodielectric are decreased with thickness. The results show that the optimized thickness should be within the range of 400–600 nm to obtain optimized properties using chemical solution deposition processing, which will provide a useful guidance to prepare the multiferroic BiFeO3 thin films.