Grounded in a dual critique of idealism and old materialism, Marx broke free from the swaddles of capitalist ideology, and constructed a scientific practical materialism by taking the social practice of human subjects as the starting point of thought. Regrettably, however, Marx’s practical materialism has been misinterpreted in later times as a kind of rigid determinism, and this has aroused the enthusiasm of scholars, of which the French philosopher Alain Badiou is a prominent representative, to reconstruct materialism. Taking over Louis Pierre Althusser’s emphasis on the “material contingency and chance”, Badiou, with the help of mathematic ontology, constructed a new materialism between “inexistant” and “existence”. However, due to the deviation from Marx’s practical materialism, Badiou’s theoretical construction, though injecting new vitality into materialism, is also in deep trouble. In a certain sense, reviewing the vitality and dilemmas of Badiou’s new materialism will help the deep development of foreign Marxist studies in China.