Being a carbon-based hybrid, graphene-semiconductor composites have attracted considerable attention in recent decades owing to their potential features such as high photosensitivity, extended light absorption, and effective separation of charge carriers, thus have been regarded as a promising platform for environmental and biomedical applications, respectively. In this mini-review, we first summarized the recent advancements in the development of graphene-based semiconductor nanocomposites via sol-gel, solution mixing, in situ growth, hydrothermal, and solvothermal approaches, and then comprehensively reviewed their potential light activated cancer phototherapeutic applications. Finally, we rationally analyze the current challenges and new perspectives for the future development of more effective phototherapeutic nanoagents. We hope to offer enriched information to harvest the utmost fascinating properties of graphene as a platform to construct efficient graphene/semiconductor hybrids for cancer phototherapy.