Abstract: Characteristic analysis on short-circuit current for asymmetric bipolar modular multilevel converter（MMC） based multiterminal direct current（MMC-MTDC） grid with dedicated metallic return（DMR） is the foundation of its fault type discrimination and fault isolation. The characteristics of short-circuit currents with different faults are similar, which are difficult to distinguish.This paper analyzes the short-circuit current characteristics of asymmetric bipolar MTDC grids. Firstly, the equivalent circuit of the MTDC grid is established, where the converter and overhead line are simplified to RLC series circuit and RL series circuit,respectively. Then, based on this, the short-circuit current characteristics of a single-terminal converter station are analyzed.Finally, based on the short-circuit current characteristics of a single-terminal converter station, the short-circuit current characteristics of the asymmetric bipolar MMC-MTDC grid with various faults are studied by analyzing the discharging circuit of MMCs. Simulation results on the Zhangbei bipolar MMC-MTDC grid of China validate the correctness of the characteristic analysis on short-circuit current for MMC-MTDC grids.