We combined the mercury passive sampling method and plant biomonitoring together to understand the long-term changes of atmospheric mercury concentrations on the Tibetan Plateau. Through the analysis of leaves of Androsace tapete that represent growing periods spanning the past decade, we explored the historical records of atmospheric mercury from 2006 to 2015. Mercury concentration was stable in the leaves of Androsace tapete during the period between 2006 and 2009, while a significant decrease occurred after the year of 2010. The decreasing trend is consistent with the monitoring data of the ground-based stations in other regions globally. Despite the potential uncertainties using a passive sampling method and biomonitoring technique, we suggest that Androsace tapete is a potential biomarker that could provide reliable and effective historical records of atmospheric mercury concentrations and offer new perspectives in monitoring mercury and perhaps other atmospheric pollutants in regions where long-term active monitoring was missing.