The invention discloses a short circuit current calculation method for a converter grid-connected distributed power supply. The method comprises steps: 1) distribution network system power supply andnetwork frame structure parameters are given; 2) rated and operation parameters of the converter grid-connected distributed power supply are given; 3) fault parameters are given; 4) initial values ofpower grid node voltage and distributed power supply output current are set; 5) short circuit current calculation is carried out based on a built impedance matrix and a node voltage equation; 6) whether the short circuit current calculated in the step 5) meets a convergence condition is judged, a step 8) is carried out and a short circuit current calculation result is outputted in the case of convergence, and in the case of not convergence, a step 7) is carried out; 7) according to the distributed power supply grid-connected point voltage, the output current is changed, and the step 5) is carried out; and 8) the short circuit current calculation result is outputted. The working mode of the distributed power supply and the reactive power support characteristics in the case of low voltage can be considered comprehensively, and the short circuit current outputted by the converter grid-connected distributed power supply during the fault period of the distribution network can be reflected more truly.