In recent years, the gravity energy storage system (GESS) based on solid medium as an energy storage unit has been extensively studied as an emerging energy storage method. Since gravity energy storage uses a solid medium as the power conversion unit, the output power has the characteristics of dispersion. The existing research mainly focuses on suppressing the intermittent and volatile power of the system when running in parallel, but the start-up and grid-connected process of it has not yet been studied. Firstly, for the vertical and ramp-type GESS, system composition, capacity, and output power is analyzed, and secondly, for the grid-connected GESS of electrically excited synchronous motor, the starting method and starting control strategy of the auxiliary motor are proposed, and then, an adaptive grid-connected control strategy is proposed for the grid-connected control of the above system. The effectiveness of the proposed starting method, starting control strategy and grid-connected control strategy is verified by simulation for ramp-type system. Finally, the power response characteristics of the GESS under parallel operation are simulated and analyzed. The results show that the GESS based on grid-connected excitation synchronous motor has the peak regulation capacity of the power system.