In order to evaluate the antitumor activity of red wood ants (Formica aquilonia) from Changbai mountain, ethyl acetate extract from this species of red wood ants and its ethyl acetate-soluble and water-soluble fractions were investigated for effects on proliferation and apoptosis of dRLh-84 cells using MTT assay and fluoroscopic observation, respectively. The ethyl acetate extract was able to inhibit the proliferation of dRLh-84 cells in a dose-dependent manner. Active components in the extract were transferred into ethyl acetate phase in ethyl acetate-water extraction due to low polarity so that the ethyl acetate phase also exhibited a significant inhibitory effect on the proliferation of dRLh-84 cells, which depended on dose with an IC50 of 60 μg/ml. Fluoroscopic observation indicated that the extract had an obvious apoptosis-promoting effect on dRLh-84 cells.