The important statement that “fundamentally it is because Marxism works” expresses an evaluation of Marxism,touches upon its essence and attributes,and involves the behaviors and practice of the Communist Party of China It is about the evaluation,substance,and agent of Marxism,respectively,which are interconnected links in a chain They reveal Marxism from within,first as an object,and then as a dominant force They also explain why Marxism may work and why it does work In this way,the logics of why Marxism works are mapped The evaluation that Marxism works is a summarization and conclusion;the substance of Marxism is the internal fundamental foundation for Marxism to work;and the agent is a crucial factor which determines that Marxism works The three aspects jointly interpret the essence of the statement that “fundamentally it is because Marxism works”.