In a distribution network with IIDG, the conventional short-circuit current calculation usually regards the IIDG simply as a constant current source or a voltage-controlled current source, which has problems with accuracy, calculation speed, convergence. In this paper, an artificial neural network based short-circuit current calculation is proposed. The output characteristic of IIDG during fault is analyzed, and a system simulation model is built in PSCAD/EMTDC. Typical features, such as the power transmitted over the line, the power of the load, and the voltage of bus are used to train the neural network model. In the IEEE33 bus system, the proposed method is validated and its performance is compared to the conventional short-circuit current calculation method.