Yes, Marxism is based on a scientific methodology called historical materialism. It’s too complex to be explained in a single comment, but it has an internal logic and methodology which proposes to analyze social systems in general, but especially capitalist societies in particular.

You can’t use the scientific method used in the natural sciences because you can’t put a society in a lab to study it. Social sciences require a methodology apart from the natural sciences, and Marxism has proposed historical materialism, which is very consistent and coherent approach, based on the Hegelian dialectical logic with materialism as a principle.