An electrolyte for a lithium secondary battery of the present invention may improve high-rate charge and discharge characteristics and high-temperature storage and life characteristics of a lithium secondary battery and may achieve an effect of increasing reversible capacity by simultaneously including lithium bis(fluorosulfonyl)imide (LiFSI) and a second lithium salt, as a lithium salt, while including a second additive as well as a novel borate-based lithium compound, as an additive.