Disclosed are a non-aqueous electrolyte solution for a lithium secondary battery and a lithium secondary battery comprising the same. The non-aqueous electrolyte solution for a lithium secondary battery comprises a silicon-based compound represented by a specific chemical formula and having both a hydroxyl group and a hydrocarbon group having a carbon-carbon double bond. When it is applied to a lithium secondary battery, the non-aqueous electrolyte solution improves deterioration of cycle life characteristics occurring after repeated charge/discharge cycles and prevents swelling phenomena by suppressing a decomposition reaction of an electrolyte solution even when a battery in a fully charged state is stored at high temperature or is charged/discharged, thereby enhancing the life characteristics at high temperature.