The invention relates to a method and system for simulating maximum conversion current of a multi-end direct current system. The method includes the steps of according to the system condition, determining a first calculation model of the conversion current of the multi-end direct current system and the resistance value range of each changeable resistor of the model; according to the resistance value range of each changeable resistor, selecting multiple resistance values of each changeable resistor, and obtaining multiple corresponding conversion current values through calculation of the firstcalculation model; determining the maximum one of the conversion current values to serve as the maximum conversion current approximate value of the multi-end direct current; according to a predetermined maximum conversion current exact value and a predetermined maximum conversion current approximate value of the two-end direct current, obtaining a random calculation error; according to the randomcalculation error, conducting error correction on the maximum conversion current approximate value of the multi-end direct current, and obtaining a maximum conversion current simulation value of the multi-end direct current system. By means of the method and system for simulating the maximum conversion current of the multi-end direct current system, a maximum conversion current calculation value suitable for engineering application can be fast determined.