The anti-fungal activities of four self-prepared rosinyl quaternary ammonium salts (QAS), QASA, BQAS1, BQAS2 and DQAS, were evaluated with paper disc method in this paper. The result showed that, all the QAS of rosin were bioactive to the selected fungi, Irpex lacteus, Trametes versicolor, Phanerochaete chrysosporium, Gloeophyllum trabeum, Chaetomium globosum, and Paecilomyces variotii. There were obvious inhibition halos for all QAS to the fungi. The result proved that the QAS of rosin were broad-spectrum anti-fungal. Especially, to white rot fungus Trametes versicolor, brown rot fungus Gloeophyllum trabeum and soft rot fungus Chaetomium globosum, they were more effective. When the concentration reached 3.2% (w/w), the inhibition halo diameters all met or exceeded 25mm. Among these four anti-fungal derivatives of rosin, the Gemini QAS (BQAS1 and BQAS2) had bigger inhibition halo diameters than the others, which indicated that the Gemini QAS of rosin were more anti-fungal than the normal QAS of rosin.