The present invention relates to the technical field of sunscreen spray cosmetics, and aiming at a problem of acceleration of skin ageing caused by using titanium dioxide as a lightwave barrier agent in the current sunscreen spray, disclosed are a lightwave barrier agent having high safety, a preparation method, and a sunscreen spray containing the lightwave barrier agent. The lightwave barrier agent is prepared by coating a reactant on the surface of a cerium oxide aqueous dispersion after performing reaction on chloroplatinic acid and sodium hydroxide, and comprises the aqueous dispersion of which an inner core is cerium oxide and a composite particle structure of which an outer shell is a platinum layer； and the sunscreen spray uses water as a solvent and further contains amphipathic molecule ectoin. The lightwave barrier agent of the present invention has no ultraviolet light catalytic activity, and has barrier performance on full wavelength bands of ultraviolet light； cerium oxide particles are uniformly dispersed and difficult to agglomerate； moreover, the sunscreen spray obtained from the lightwave barrier agent can use water as the solvent, and the lightwave barrier agent and the ectoin take a synergistic effect, so that compared with a sunscreen spray containing titanium dioxide, the sunscreen spray obtained from the lightwave barrier agent is safer and has a good ultraviolet-proof effect.La présente invention concerne le domaine technique des écrans solaires cosmétiques en vaporisateur, et vise à résoudre un problème d'accélération du vieillissement de la peau provoqué par l'utilisation de dioxyde de titane en tant qu'agent barrière aux ondes lumineuses dans un écran solaire en vaporisateur actuel, l'invention concerne un agent barrière aux ondes lumineuses présentant une sécurité élevée, un procédé de préparation, et un écran solaire en vaporisateur contenant l'agent barrière aux ondes lumineuses. L'agent barrière aux ondes lumineuses est préparé par revê
