The intelligent and reliable judgment of the open/closed status of the disconnector plays a crucial role in power grid dispatch. To meet the demand for comprehensive scheduling and remote control operation of disconnectors, at least two non-homogeneous indicators need to change correspondingly. Based on the peak feature of “reflective impedance increases during rotation and decreases during deformation” in the process of opening and closing of disconnectors, this paper proposes a time-domain fusion intelligent criterion for the complete open/closed position determination of disconnectors, integrating auxiliary contact as the first criterion and peak impedance as the non-homogeneous second criterion. Through case studies, the distinct impedance peak feature from opening to closing of the disconnector has been verified, and the effectiveness of the proposed method has been demonstrated. Compared with existing technologies, the technology proposed in this paper has met the requirements of high precision, low cost, high reliability, and wide applicability. It has important research and guidance value for the promotion and application of subsequent power engineering projects.