We investigate the entanglement features in the interacting system of a quantized optical field and a statically driven two-level atom, known as the asymmetric quantum Rabi model (A-QRM). Intriguing entanglement resonance valleys with the increase of the photon-atom coupling strength and peaks with the increase of the driving amplitude are found. It is revealed that both of the two kinds of entanglement resonance are caused by the avoided level crossing of the associated eigenenergies. In sharp contrast to the quantum Rabi model, the entanglement of the A-QRM collapses to zero in the strong coupling regime except that the driving amplitude equals to mω/2, with m being an integer and ω being the photon frequency. Our analysis demonstrates that such entanglement reappearance is induced by the hidden symmetry of the A-QRM. Supplying an insightful understanding on the A-QRM, our result is helpful in exploring the hidden symmetry and in preparing photon-atom entanglement in light-matter coupled system.