An electrolyte and an electrochemical device, which relates to the field of energy storage materials. The electrolyte includes an additive A, an additive B and an additive C, the additive A selected from a group consisting of multi-cyano six-membered N-heterocyclic compounds represented by Formula I-1, Formula I-2 or Formula I-3, and combinations thereof, the additive B is at least one sulfonate compound, and the additive C is at least one halogenated cyclic carbonate compound. The electrochemical device includes the above electrolyte. The electrolyte of the present disclosure can effectively passivate the surface activity of the positive electrode material, inhibit the oxidation of the electrolyte, and effectively reduce gas production of a battery, meanwhile the electrolyte can be also adsorbed catalytically active of the graphite surface to form a more stable SEI film, thereby effectively reducing side reactions