The present disclosure provides an electrolyte and a secondary battery. The electrolyte comprises: a non-aqueous organic solvent; an electrolyte salt dissolved in the non-aqueous organic solvent; and an additive dissolved in the non-aqueous organic solvent. The additive comprises a first additive, the first additive is selected from boron phosphate represented by formula 1. When the electrolyte of the present disclosure is applied in the secondary battery, the performances of the secondary battery under high temperature environment can be effectively improved.