To adapt the grid to the requirements of intelligentization and the dispatching and control cloud technology route, this paper proposes a relay protection setting calculation method for power grid based on distributed parallel computing. First, the cluster architecture of the Spark distributed computing platform is introduced, and the key issues of distributed parallel computing, such as load balancing, system fault tolerance, etc. are analyzed. On this basis, a computing system for relay protection setting calculation based on Spark is designed. Secondly, the extra-high-voltage power grid setting calculation in the computing system is analyzed, and the principles of protection and setting calculation are summarized. Next, to realize the preprocessing operation of the initial power grid data input to the system, data feature selection is realized by improving the monarch butterfly optimization algorithm. Finally, simulation analysis was conducted on specific instances in a region to verify the effectiveness of the system. The simulation results prove that the computing system enables the setting calculation of the power grid to accommodate intelligentization and the development of dispatching and control cloud, which can effectively increase the calculation speed and improve the reliability of power grid operation.