Abstract: With the development of the Inner Mongolia power grid, short-circuit current exceeding the standard has become one of the most prominent problems in recent years. The asynchronous interconnection model of back-to-back HVDC transmission system was established with the planned Inner Mongolia 500kV power grid in 2023 as the research target. Based on the model, PSD-SCCP was uesed to scan the entire network for three-phase and single-phase short-circuit currents on 220 and 500kV buses before and after the Inner Mongolia Power Grid Asynchronous Networking Project was connected. It can be concluded that after the asynchronous network project was put into operation, it could reduce the overall short-circuit current level of the Inner Mongolia power grid to a certain extent, especially the effect of limiting the short-circuit current level of the bus near the converter station was very obvious. However, for areas that is far from the converter station, the restriction effect was not obvious. The effectiveness and limitations of asynchronous networking schemes in limiting short-circuit current were verified. Therefore, for the short-circuit current exceeding the standard of the Inner Mongolia power grid in 2023, a combination of asynchronous networking solutions and other traditional measures to limit short-circuit current can be adopted to deal with it.