The power system is gradually becoming an AC/DC hybrid MES (multi-energy system) with hydrogen energy. Due to the uncertainty of reactive power demand of load in MES and the multi-time scale characteristics of different energy flow transmission. It will lead to difficulties in reactive power coordination within the entire MES. Secondly, in response to this problem, this paper first establishes a MES cluster hybrid power flow equation formed by AC/DC and hydrogen transmission channels. The reactive power voltage fluctuation characteristics of AC/DC systems under MES cluster interconnection channel energy exchange, system energy conversion and renewable energy output fluctuation are analysed. Then according to the MES cluster hybrid power flow calculation. The main factors affecting the voltage reactive power of the AC system are studied, and the reactive power model based on electrothermal conversion, hydrogen storage and multi-energy transmission channels is established. Finally, proposed an algorithm for generating the safety and stability boundary of pipe network pressure. It’s used to construct the safe and stable boundary of the system pipe network. based on the actual operational data of multi-energy power system. The simulation model of reactive power dynamic optimization control for multi-energy interconnected systems is established