This paper constructs a cognitive analysis frame for multimodal critical metaphor, through the lens of multimodal discourse analysis, and by incorporating critical metaphor analytical procedures by Charteris-Black and the conceptual blending theory in cognitive linguistics. It analyses the ideology and inherent meanings behind 60 cartoons about "crackdown on gang crimes" from the perspective of cognition. It is concluded that orientational metaphor and war metaphor are used in the cartoons. There are three target domains, including "law enforcement officer", "mafia-like gangs" and "protective force". The multimodal "beat scenario", "deinsectization scenario" and "umbrella-pull out scenario" are constructed with the help of image modality, literal modality and many kinds of metaphors. The cognitive analysis frame for multimodal critical metaphor can deeply explain the generative mechanism and cognitive mechanism of the meaning of the cartoons, which could contribute to people's in-depth understanding of the cartoons.