Two star polycations, poly(2-aminoethyl methacrylate) (PAEMA, P1) and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA, P2), have been synthesized with perylene diimide (PDI) as the central fluorophore. 1H NMR and 13C NMR are used to confirm the successful synthesis of a macromolecular initiator. Using ATRP strategy, P1 and P2 are obtained with narrow molecular weight distribution. The star polymers have good fluorescence properties in aqueous solution, which provides fluorescent tracing and imaging during gene delivery. Both P1 and P2 can efficiently condense DNA into stable nanoparticles. Transfection studies demonstrate that P1 and P2 deliver DNA into live cells with higher efficiency and lower cytotoxicity than polyethylenimine (PEI, 25 kDa). P2 shows higher capacity for gene delivery than P1 due to its better buffering and faster rate of cellular internalization.