The invention provides a network pressure detection method of an intelligent substation relay protection device and related systems. The method comprises the following steps: selecting a tested area in an intelligent substation and a tested relay protection device in the tested area; and separately performing process layer network pressure detection and station control layer network pressure detection on the tested relay protection device. The related systems comprise a process layer network pressure detection system for the relay protection device and a station control layer network pressure detection system for the relay protection device. By adoption of the method and the related systems provided by the invention, the most severe network pressure environments of different types that may be occur can be simulated accurately and reliably in high authenticity, and the requirements of performance test of the relay protection device in different process layer non-subscription message network pressure environments are satisfied; and the problems that the network pressure environment of the intelligent substation cannot be truly simulated and that the action performance of the intelligent substation relay protection device cannot be fully tested under the network pressure are solved.