The standard model of particle physics is the most successful theory in describing the fundamental microscopic structure of matter in the universe. It consists of the theory of quantum chromodynamics for the strong interaction, and the electro-weak theory for the weak and electromagnetic (EW) interactions. In the quantum chromodynamics (QCD) theory, the nature of the quark confinement and low-energy non-perturbative property is still not clear; in the electro-weak theory, more stringent parameter constraints and experimental tests are required. The Beijing Electron-Position Collider (BEPCII) and Beijing Spectrometer (BESIII) are amongst the earliest largescale scientific facilities in China, and the only ones in the world still conducting high-luminosity experiments in the tau-charm energy region. They focus on research in hadron physics, non-perturbative effects in QCD, precision tests of the EW theory, and the search for new physics beyond the standard model. This article will review the highlights of the BESIII experiments during the past decades, such as the precise measurement of the tau lepton mass, the R
value measurement, studies on the exotic hadrons, and measurements of the charmed hadron weak decays.