Firstly, the spherical Fe50Ni50 powders, particle size about 100 nm, were prepared by liquid phase reduction method, and then were mixed with butyl rubber (IIR) dispersed in liquid. Fe50Ni50 powders/IIR nanocomposite films, powder mass fraction was 65 wt%, were harvested through being mixed and milled lastly. The force sensitive properties of the films were studied under the condition of that the loading/unloading speed of the stress was 0.10 mm/min controlled by the LYYL-500N high-grade microcomputer controlling compression-testing machine, and the test frequency of impedance (Z) was 1 kHz tested with the TH2816B LCR digital electric bridge. Results show that Fe50Ni50 powders can be dispersed uniformly as nanometer scale in this nanocomposite by liquid phase mixing method. And the Fe50Ni50 powders/IIR nanocomposite film, thickness 185 mu m, has excellent force sensitive properties when the stress is between 0.20Mpa and 0.90Mpa. The impedance stress curve appears approximately linear decline, and stress sensitivity vertical bar k vertical bar value is stable in 40-60, stability S value is about 1 similar to 2 k Omega, and the film enters into a steadily sensitive stage responding to stress. (C) 2016 Elsevier B.V. All rights reserved.