Abstract: Because of the extraction of geothermal resources, Wang-4 well has dried-up and stopped observing in December 2008.In order to pump water and study the observation of water mercury, the equipments modification of the observation well had been done in 2010.To ensure the new observation data is stable and reliable, the pumping tests have been conducted to research the influence of pumping conditions and pumping time.The results show that the pumping time and the pumping position have little effect on measured values of water mercury, and this is consistent with the chemical properties of water mercury. Consequently, this paper proposed that we still can choose sensitive observation sites for water mercury measurements monitoring in the region without artesian well in certain observation conditions.