The invention discloses a biodegradable alkyl acetamidobenzotriazole derivative lubricating oil additive which does not contain sulfur, phosphorus, halogens and metal elements as well as a preparation method and application thereof. The preparation method comprises the following steps: under the action of alkali, performing amidation on alkyl amine and chloroacetyl chloride to obtain alkyl chloroacetamide; and then performing a nucleophilic substitution reaction with benzotriazole to obtain a target compound of a formula I. The preparation method disclosed by the invention is simple in preparation method, mild in process condition, easily available in raw material, low in preparation cost and high in synthetic yield. The novel alkyl acetamidobenzotriazole derivative can be independently used as an extreme pressure anti-wear corrosion-resistant additive of lubricating oil, also can be used with other lubricating oil additives in a compound manner, also can be used in common working conditions and high-temperature working conditions, can improve the bearing capacity of basic oil obviously and improve the anti-wear performance, and is the lubricating oil additive which is environmentally friendly and multi-functional. The formula I is as shown in the specification.