Compared with wired networks, wireless networks have more practical features. One of the main problems in wireless channels is fading, in which the channels change randomly that results in degrading the performance of the wireless system One way to deal with this effect is using cooperative communication. Relay increases the coverage and the capacity of network and reduces power consumption. Moreover, the efficient use of radio spectrum has introduced another subject called cognitive communication in which the available spectrum is used more efficiently. As well as the efficient use of radio spectrums the issue called cognitive communication, has raised, in which the available spectrums are used more efficiently. Cooperative cognitive radio networks have cooperative and cognitive radio networks properties. Cooperation is used in spectrum sensing and help to send the primary user applications at cognitive radio networks and network performance is improved. esides, the new generation of telecommunication and mobile systems require high capacity and lots of energy due to large amount of information traffic. Therefore, one of the issues discussed in this field is how to supply the energy of the system. Supplying the consuming energy by charging or replacing the energy source has always been problematic and costly. Thus, the harvested energy from the environment and especially the radio frequency signal can resolve this problem in communication systems. Using cooperative systems and cognitive radio networks with energy harvesting capability can improve the system performance. In this thesis, a system model for cooperative cognitive radio networks with energy harvesting capability is proposed. In the proposed system model one of the secondary users with selection as a relay to send the primary user information and all secondary users harvested energy from radio frequency signal. Mathematical analysis and simulation of the outage probability of the primary and secondary users are investigated. Moreover, the available parameters and their impact on the proposed model are discussed. Impact of relay selection methods, cognitive radio multi-user systems and secondary user transmission fairness methods on the proposed model have been investigated.