τ mass and R value measurements at BES

A comprehensive review of the measurements of $\tau$ lepton mass and $R$ values in the energy region between $2-5$ GeV, achieved at the BES experiment, is presented. In addition to the evaluation of their impact on the test of Standard Model, we also highlighted the present status and the most recent developments. In particular, we made an extensive discussion on the prospects for future improvements at the BESIII experiment.