This document describes the main magnetospheric large-scale current systems and the magnetic field in the Earth's magnetosphere and provides the main requirements to the model of the magnetospheric magnetic field. Ionospheric currents are not considered in this document. The document also provides a working example of the model and establishes the parameters of magnetospheric large-scale current systems which are changing in accordance with conditions in the space environment. The document can be used to develop the new models of magnetospheric magnetic field. Such models are useful in investigating physical processes in the Earth's magnetosphere as well as in calculations, developing, testing and estimating the results of exploitation of spacecrafts and other equipment operating in the space environment.