The development of high-performance stretchable and electromagnetic interference (EMI) shielding materials is crucial to the rapidly growing industry of next-generation flexible electronics such as portable electronics and wearable devices. The common approach to EMI shielding is to increase the contents of conductive materials and improve the conductivity. However, this approach is limited by the worse stretchable property. An intrinsically stretchable conductive and EMI shielding thin film (thickness of 0.7 mm) based on functional adhesive (FA) composited by silver nanoparticles (Ag NPs), nickel nanoparticles (Ni NPs), and liquid polydimethylsiloxane (PDMS) is proposed in this paper. The FA is coated onto cured PDMS substrates to fabricate the film, achieving maximum tensile strain of 250% and EMI shielding effectiveness (SE) of 57.1 dB. Up to 35% absorptivity makes an important contribution to SE. This film can withstand more than 20000 stretching-releasing cycles at tensile strain of 0-100% and 0-150%, with no delamination, demonstrating its superior stretchability and repeatability. The mechanism of EMI shielding of silver and nickel nanoparticles is discussed. The durability of these films in terms of electrical and EMI SE properties are also tested. In addition, a device to change the output power of a transformer is constructed.