The 2nd CEPC Physics Workshop toward TDR will take place between January 13-15, 2020 at IAS in Hongkong. The Circular Electron Positron Collider (CEPC) is a future Large Scale Collider facilites. Installed in a 100 km tunnel, the CEPC could produce 1 Million Higgs bosons, 100 Million W bosons, and nearly 1 trillion Z bosons in 10 years' operation. The prior physics motivation of CEPC is to serve as a precise Higgs factory, meanwhile, it also has a huge physics potential on the EW, QCD, Flavor physics and new physics hunting. The workshop intends to gather scientists around the world to profound study the physics potentials at the CEPC, to address the critical technical requirements (theoretical uncertainty control, interpretation, combination, etc) and develop initial plans towards Technical Design Reports (TDR). This workshop serves as a forum to discuss all those critical questions and looking forward to your active participation.