This application provides an electrolyte and an electrochemical device, in which the electrolyte comprises an additive A and an additive B, wherein the additive A is present in an amount of 0.01% 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 and the electrolyte has a conductivity of 6 mS/cm to 10 mS/cm at 25° C. The present invention can improve the cycle performance and storage performance of the electrochemical device, in particular, improve the cycle performance and storage performance of the electrochemical device under high temperature and high voltage conditions while keeping the low temperature performance.