Abstract: Assuming that unstirring stripping prccess of the metal in the amalgam is controlled by the limited flox of the oxidant and providing that setting time is not less than 30 second, a theory of unstirring potcntiometric stripping analysis (UPSA) with hanging mercury drop elctrode(HMDE) is presented in this paper. Experimental verification is made and it was found that the experimental results arc in agreement with the theoretic conclusion, and so the theory of UPSAis successfully approached.