The invention belongs to the technical field of lithium ion batteries, and discloses a high-voltage functional electrolyte containing (2-allylphenoxy) trimethylsilane additive and a preparation methodand application thereof. The high-pressure functional electrolyte containing (2-allylphenoxy) trimethylsilane additive comprises a cyclic carbonate solvent, a linear carbonate solvent, a conductive ion lithium salt and (2-allylphenoxy) trimethylsilane. The invention also provides the application of the high-voltage functional electrolyte in the field of lithium ion batteries. A lithium ion battery prepare from that electrolyte of the invention has good charging and discharge performance. The high-pressure functional electrolyte containing (2-allylphenoxy) trimethylsilane additive of the invention can be used in the range of 3. A stable protective film is formed on the surface of the cathode material during the charge/discharge process of 5V, which not only inhibits the oxidation decomposition of the high voltage electrolyte, but also protects the cathode material, so as to improve the cycle stability of the high voltage lithium ion batteries.