In this talk, I present the potential physics program of the super $\tau$-charm factory (STCF). The STCF is an electron-positron collider with a center-of-mass energy ranging from 2 to 7 GeV and an instantaneous luminosity greater than $0.5\times 10^{35}$ cm$^{-2}$s$^{-1}$. This energy region corresponds to the transition between non-perturbative quantum chromodynamics (QCD) and perturbative QCD. Hence, a large variety of topics in elementary particle physics can be pursued at STCF, including exploring QCD and hadron spectroscopy, precise measurement of electroweak interactions and flavor physics studies as well as searches for the new physics beyond the standard model.