The invention provides a topological structure for a direct-current power transmission and distribution project dynamic simulation experiment system. The topological structure comprises at least fourMMCs and high/medium-voltage direct-current buses corresponding to the four MMCs, wherein the direct-current sides of the MMCs are connected with the high/medium-voltage buses through direct-current circuit breakers to form serial and parallel loops; alternating-current sides of the MMCs are connected with an alternating-current bus through an alternating-current transformer, a starting loop and an alternating-current circuit breaker; part of the high/medium-voltage buses are connected with a grounding electrode through the direct-current circuit breakers; an LCC is arranged between the alternating-current bus and the high/medium-voltage direct-current buses; a rectifier AC/DC is arranged between the alternating-current bus and a low-voltage direct-current bus; a bidirectional converter DC/AC is arranged among the direct-current buses, a direct-current power source and a load; direct-current converters are arranged between the high/medium-voltage direct-current buses and the low-voltage direct-current bus and between an alternating-direct-current power source and the load. The topological structure solves the problem that when an existing dynamic simulation experiment system is used for a direct-current power transmission and distribution project, the adaptability and the flexibility are poor.