In view of the technical difficulties in the preparation of NiAl alloy sheets and the secondary forming of the complex thin-walled components, a new integrated process of forming and in-situ reaction is proposed to manufacture NiAl alloy thin shell parts. First, the Ni foils and Al foils are alternately stacked in the mold and plastic forming is performed under the action of solid granules medium, then the formed Ni/Al laminated thin shell parts continue to stay in the mold and are heated under the pressure of the solid granules medium, leading to the in-situ reaction of Ni/Al layers into the NiAl alloy. Finally, the NiAl thin shells are manufactured. The microstructure of the component was characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), and the high temperature mechanical properties were tested. The results show that the NiAl alloy conical shell is composed of single NiAl phase, and the coarse crystal layer and fine crystal layer are alternately distributed in the thickness direction, which is a typical bimodal structure without holes and other defects. The component hardness is 317HV and the distrbution is uniform, the tensile strength is 71 MPa at 1000 ℃, and the elongation can reach 74%.