A composite negative active material, and a negative electrode and a lithium secondary battery that include the composite negative active material, and a method of preparing the composite negative active material are disclosed. The composite negative active material includes: a core including a silicon material and a coating layer disposed on the core, wherein the coating layer includes a water-insoluble polymer composite in which at least one anionic component is chemically bonded to a water-soluble polymer, thereby improving lifespan characteristics of the composite negative active material.