Abstract: A systematic study on the interaction between 2-（3,5-dimethyl-pyrazol-1-yl）-6,8-dimethyl-4b,9-dihydro-1,5,8 a,9-Tetraaza-Fluorene（PTF） or its metal complexes and salmon sperm DNA was investigated using ultraviolet（UV）, fluorescence, circular dichroism（CD） spectrum and viscometric method under simulated physiological conditions. Our results showed that the PTF can form a complex with Cu（Ⅱ） and Zn（Ⅱ） at a coordination ratio of 2∶1. A significant hypochromic effect on the UV spectrum of DNA was appeared after the action of PTF,PTF-Cu（Ⅱ） and PTF-Zn（Ⅱ）, accompanied by the equal absorption points, closed to the 2∶1 molar ratio of combination. After a series of interactions of three PTF or its metal complexes, the fluorescence spectrum of the DNA was quenched and their binding site n is close to 1. The amplitude of positive and negative peaks of CD spectrum decreased significantly, especially in the trend of action of PTF-Cu（Ⅱ） and PTF-Zn（Ⅱ）. The relative viscosity and denaturation temperature of DNA increased in turn after the action of PTF, PTF-Cu（Ⅱ） and PTF-Zn（Ⅱ）. Moreover,the PTF, PTF-Cu（Ⅱ） and PTF-Zn（Ⅱ） all had good antibacterial activities on Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Cruciferous black rot. As a whole, our comprehensive analysis showed that the interaction modes of PTF, PTF-Cu（Ⅱ）, PTF-Zn（Ⅱ） and DNA were all intercalation, and the binding ability trend was PTF-Zn（Ⅱ）＞PTF-Cu（Ⅱ）＞PTF.