With the large-scale integration of new energy stations and induction motors into distribution networks, their impact on the short-circuit current characteristics of the network has become increasingly significant. Existing short-circuit current calculation methods are difficult to accurately reflect the combined effects of these diverse feeding sources. Therefore, this paper proposes a steady-state current calculation method for three-phase short-circuit faults in distribution networks with large-scale multi-type feeding sources. First, the waveform of the three-phase short-circuit current fed by induction motors during faults is fitted through waveform modelling, and an equivalent relationship is established between a detailed distribution network model and its equivalent model. Then, simulation results verify that the equivalent model has high consistency with the detailed model in both steady-state and transient characteristics. Finally, under conditions of large-scale integration of new energy stations and induction motors, the equivalent models of new energy stations and distribution networks are jointly represented as voltage-controlled current sources for calculating the steady-state current of three-phase short-circuit faults. Simulation results show that the proposed method has high computational accuracy and strong engineering practicality.