Helium behavior in W/Ni bilayer nanocomposite was investigated by neutron reflectometry, transmission electron microscopy (TEM) and density functional theory (DFT) calculation. Under He' ion implantation, the helium enriched layers are formed at W/Ni interface. As the implantation fluence increases to 1 x 10(17) ions/ cm(2), the helium bubbles are observed in W and Ni layer, and the adsorption of helium atoms reaches saturation at W/Ni interface. Moreover, a mechanism that helium atoms trapped at the interface of W/Ni mainly migrate from the W layer is proposed. This mechanism enlightens that dispersing nickel-nanoparticles into tungsten can protect tungsten against helium deleterious effect. That is, modulating the constituent of dispersed nano-particles can effectively improve the helium resistant of materials.