Organometal halide perovskite materials are emerging as solar cell materials, but the understanding of its performance is not yet enough, especially in its ferroelectricity which is important for the separation of photo-generated carriers. In this paper, we report investigations on influences of annealing temperature on the ferroelectricity of solution-processed methylammonium lead triiodide (CH3NH3PbI3) thin film. It is found that annealing temperature has significant effect on the crystallinity and the crystal size, which further affects the ferroelectricity and the luminescence property. It indicates that the crystallization degree of the thin film and the uniformity of crystal growth are gradually getting better, and the phase contrast of positive polarization areas and negative polarization areas are gradually strengthened. (C) 2015 Elsevier B.V. All rights reserved.