A transparent constraint apparatus for the normal deformation of a planar model, including rigid transparent retainer plates, a planar model, and magnetic force components. The magnetic force components are provided at edge positions of the rigid transparent retainer plates; the normal direction of the planar model is parallel to the normal direction of the two rigid transparent retainer plates, and said two retainer plates are symmetrically arranged relative to the plane of symmetry of the planar model; the magnetic force components are symmetrically arranged relative to the plane of symmetry of the planar model, mutually symmetrical magnetic force components producing mutually attractive magnetic force. The transparent constraint apparatus solves the problem of constraining the normal deformation of a planar model under planar-strain conditions during testing.