This application provides an electrolyte and an electrochemical device, wherein the electrolyte comprises an additive A and an additive B, the additive A is present in an amount of 0.001% to 10% by mass in the electrolyte, and the additive B is present in an amount of 0.1% to 10% by mass in the electrolyte. This application can improve the cycle performance and storage performance of the electrochemical device, especially the cycle performance and storage performance of the electrochemical device under high temperature and high voltage conditions.