Provided are an electrolyte for a high-voltage lithium secondary battery and a high-voltage lithium secondary battery containing the same, and more particularly, an electrolyte for a high-voltage lithium secondary battery which may not be oxidized and decomposed at the time of being kept at a high voltage and a high temperature to prevent swelling of a battery through suppression of gas generation, thereby having excellent high-temperature storage characteristics and excellent discharge characteristics at a low temperature while decreasing a thickness increase rate of the battery, and a high-voltage lithium secondary battery containing the same.