Abstract: There are many problems in the ideological security capacity building of democratic parties. The construction, identification and dissemination of Marxism by some members of the democratic parties needs to be improved. Hostile forces use neoliberalism and historical nihilism to disrupt ideological security. In the new era, the erosion has become tighter and the damage has become more severe. The mainstream ideology of Marxism has been questioned, and the ideological security capacity building of democratic parties has been eliminated. To this end, it is necessary to strengthen the party’s ideological security capacity building, consolidate the material foundation for the democratic parties’ ideological security capacity building, and forge a public opinion platform for the democratic parties’ ideological security capacity building.