Abstract: PTZ(pan-tilt-zoom) cameras have been widely used in visual surveillance domain due to their ability to cover wide field of view and large scale range. For the large demand of intelligent visual surveillance, a novel multi-resolution active tracking method was presented based on two PTZ cameras. The proposed method consists of two stages: off-line calibration and on-line cooperative tracking. In off-line calibration stage, a novel method was presented that combines feature based single-PTZ camera self-calibration and object motion based dual-PTZ cameras self-calibration. The proposed approach doesn't require calibration tools and manual operation. Two important properties of proposed system were also inferred based on above calibration method. In on-line tracking stage, a piecewise cooperative tracking strategy was designed. The verification of proposed algorithm framework was implemented on real outdoor surveillance environment. Experimental results show that the proposed method can track the moving object effectively. The proposed framework can be used in intelligent visual surveillance with wide application prospect.