PEG-PLGA was used as the capsule material, and added by photosensitizer pheophorbide to make photo responsive Cobra neurotoxin (CNT) nanocapsule by double emulsion method. The formula was optimized by with encapsulation efficiency, drug loading and particle size as the indexes by single factor tests. Its structure, The thermo rheological properties were analyzed by differential scanning calorimeter, and photo responsiveness were was analyzed by cumulative release. The optimal ratio of PEG-PLGA , CNT and pheophorbide was 40:12.5:1, and the encapsulation efficiency 72.3%±3.6%, drug loading 15.1%±1.3%, average particle size (862±23) nm, and zeta potential (-46.5±3.8) mV were obtained with tight spherical shape and pheophorbide in outer layer of the nanocapsule. Drug release was accelerated under illumination of 650 nm for 30 min with semiconductor laser. This new type of nanocapsule can keep drug stable and sustain release without illumination, but release quickly under red light, thus light controlled targeting can be achieved.