String theory may be the fundamental theory that describes the nature close to the Planck scale. How to test the string theory at the Large Hadron Collider (LHC) is an interesting question. I will consider a few scenarios: high-scale supersymmetry breaking and its prediction on Higgs boson mass; string-scale gauge coupling unification in the weakly coupled heterotic string theory and its prediction of vector-like particles; and intersecting D-brane models. Furthermore, I will discuss the string inspired singlet extensions of the Minimal Supersymmetric Standard Model with new Higgs physics.