A fusion protein and a complex containing same, capable of being used for the intracellular delivery of cargo molecules. The fusion protein and complex can implement the efficient release of cargo molecules from endocytic vesicles, thereby significantly improving the cytoplasmic delivery efficiency of the cargo molecules. One cargo molecules can be obtained in cytoplasms, they can exert any function related thereto. The fusion protein and complex provide effective means for affecting biological mechanisms and pathways of cells, and can be used in various fields such as research, treatment, and diagnosis.