Traditional interfacial toughness measurements for thin films on substrate are not appropriate to the structure composed of stiff films and soft substrate. This paper describes a new bending test system to measure the interfacial toughness for the soft interface between stiff films and elastomeric substrate. The experimental setup including the loading stages is easy to operate and scanning electron microscope is used to in situ monitor the interfacial slippage during loading. The proposed bending test is conducted for silicon film on poly(dimethylsiloxane) substrate. This method demonstrates the promising way to measure the slippage toughness of soft interface involving the flexible electronics and the bio-related fields.