Abstract: The field of new compounds and synthesis methods thereof are related, and particularly to a structure of a steric hindrance adjustable weak base light stabilizer and a preparation method and application thereof. According to the innovative light stabilizer, a steric hindrance thereof is adjusted by establishing substituent generating the steric hindrance around nitrogen atoms; moreover, an electronegativity of the nitrogen atom can be influenced by adjusting a distance of a polar group, so that an alkalinity or a nucleophilicity of the nitrogen atom is adjusted. A desired effect is obtained by adjusting a steric hindrance and a nucleophilic property or an alkalinity where the nitrogen atom is located, so that an application range of the innovative light stabilizer is widened, and the innovative light stabilizer is suitable for PC, polyester, PVC and other slightly acidic or certain electrophilic polymer materials to serve as a light stability protecting aid.