The combinations of microflow technology and photo-induced reversible-addition fragmentation chain transfer polymerization (photo-RAFT) and light-mediated polymerization-induced self-assembly (light-PISA) have enabled distinguished advantages that cannot be done in the traditional batch reactor. Recently, well-defined polymers with precise chemical and topological structures, and advanced nano-objects with high-order morphologies have been reported by using microreactor-based photo-RAFT and light-PISA strategies. In this mini-review, continuous flow photoiniferter polymerization, RAFT with photoinitiator, and PET-RAFT are summarized in order. Moreover, the emerging light-PISA in microflow is introduced, and finally, the remained challenges are proposed for the discussion of opportunities. We hope it would provide insights into flow chemistry, polymer precision synthesis, and nanoscience.