Amorphous fluoropolymer (AF) thin films have been prepared from Teflon AF 1600 solution by spin-coating. Scanning electron micrograph (SEM) observations reveal that the film has planar and compact surface without any pinhole, and there are many pores in the matrix. By capacitance-voltage (C-V) and current-voltage (I-V) measurements, the dielectric constant of the AF film is equal to 1.57 at 1 MHz, and breakdown strength is 2.07MV cm−1. The Fourier transform infrared spectroscopy (FTIR) spectra and X-ray diffraction (XRD) patterns of the films show that the films have excellent thermal stability below 400℃, and thermal treatment does not change amorphous nature of the films. X-ray photoelectron spectroscopy (XPS) spectra reveal decomposition of CF3 groups due to annealing at 400℃, leading to a remarkable increase in CF2 groups. Possible decomposition mechanisms of AF film are also discussed.