An electrical system assembly of an electric automobile includes an energy system, a power system, and an instrument system. The energy system includes a battery module and a management module for managing the battery module; the power system includes a motor and a controller; the battery module includes a number of storage batteries connected in series and a solar panel for charging the storage batteries; and the storage batteries provide energy to the controller, controlling the motor through the controller. There is communication between the management module, the controller and the instrument system, thereby each of these is capable of knowing the working status of the other two, thus facilitating coordination and enabling a powerful protection function for the electrical system assembly of the electric automobile.