This research examines the JCPOA agreement on Iran's oil market in the network of oil markets for the time period of 1991/11 to 2019/2 using Diblad Yilmaz's spillover index and complex network theory.The time period of this research was divided into three time periods before JCPOA, JCPOA and after withdrawal from JCPOA. In all three periods, the Iranian oil market is the transmitter of turbulence in the oil markets.During the implementation of JCPOA, the Iranian oil market sent more turbulence to other oil markets. which shows the increase in the turbulence of the Iranian oil market during the implementation of the JCPOA and the increase in the influence of the Iranian oil market in the oil market network.During the implementation of the JCPOA, the transmission power of the turbulence of the Iranian oil market has increased. Oman's oil market, before the implementation of the JCPOA and after the withdrawal from the JCPOA, has been the most turbulent transmitter in the oil market network. During the implementation of the JCPOA, the Indonesian oil market has been the most sender of turbulence in the spillover network.