In order to study and analyze the effective means of reliability, voltage stability, and efficient operation of the current complex distribution network system with new forms, a synchronous interface algorithm for multi flow fusion simulation considering energy flow, information flow, control flow, and business flow was studied. Four typical interface algorithms were compared and studied, and an improved ideal transformer model (ITM) interface algorithm based on feedback current filtering was studied. The results indicate that this method optimizes the stability conditions of the ITM algorithm by feeding back the current measured on the physical side to the digital side through a filter, reduces the delay on both the digital and analog sides, and improves the stability and accuracy of the multi flow fusion simulation system. It can be seen that the ITM improved interface algorithm based on feedback current filtering effectively balances the stability and accuracy requirements of the synchronous interface in real-time simulation of multi flow fusion in the distribution network.