Abstarct: Abstract With the expansion of the electricity network, the possibility of faults occurrence and lack of access to the network increases. The use of new equipment with different operating conditions causes the transmission of electrical energy with the desired quality to be a serious challenge. Therefore, it is important to enter into the topic of reliability in order to answer such challenges. Transmission lines are introduced as the main factor of electric energy transmission, whose optimal performance is limited from the point of view of electric power transmission capacity. The use of superconducting technology has solved many of the existing needs related to the limitation of electric energy transmission, and many advanced countries use it as a useful tool to overcome these challenges. However, this technology in cables has made their examination from the point of view of reliability to be considered. Considering the performance of this equipment in cryogenic temperature, the superconducting cable system consists of two dimensions, the cable system and the cooling system. In this thesis, the reliability modeling of superconducting cable considering the conditions of its cooling system has been investigated using the Markov method. In general, the superconducting cable system consists of several parts, including the cooling system, the terminal system, and YBCO type superconducting cable. The Markov model has been presented for each of the parts. Cooling reliability modeling was done in three separate models and its extended Markov model was extracted. The composition of the Markov model for different sections was finally analyzed and evaluated in three main designs for the exploitation of superconducting cable. Extended Markov models of 12, 12 and 9 states for the main designs are obtained and their results are presented. The simulation results have shown that the proposed model provides favorable conditions for evaluating the reliability of the superconducting cable system. The results have shown that all these designs have the desired performance. However, despite the improvement of the operating conditions, the hybrid cooling system has led to a decrease in the reliability of the superconducting cable system.