It was the first in China that an attempt was made at screening houseplants to remove ammonia from indoor air. A fumigation system was used to screen 86 species and cultivars at 7.0 mg/m3 of ammonia in the initial screening experiment. Then 9 species of plants were chosen for replication experiment to confirm and quantify the removal effects. Plants in Ericales order showed a promising potential for removing ammonia and further study was suggested. Finally, Nephrolepis exaltata ‘Bostonniensis’ and Plectranthus oertendahlii were fumigated in day-and-night experiment. And the trends of removal rates of ammonia dependence on fumigation time were predicted as cubic functions for both species.