Echinacea is valuable for its pharmaceutical, medicinal and agricultural properties. Flowers and leaves of Echinacea purpurea (L.) Moench and Echinacea pallida (Nutt.) Nutt. were extracted with methanol, filtered, and solvents were removed by rotary evaporator to get four separate extracts. The flowers and leaves of both plants were boiled in water then extracted with ethyl acetate to achieve another four extracts. Quantifications of chemical constituents of extracts were determined by TOF-LC/MS. The main compound of methanol extracts of E. purpurea and E. pallida leaves and flowers was cichoric acid. Caffeic acid was the chief compound of water extracts of both plant leaves and flowers. The antioxidant activities including DPPH free radical scavenging, ABTS cation radical scavenging and reducing power were assayed and structure-activity relationships were postulated. Water extracts of both Echinaceae species of flowers and leaves revealed excellent antioxidant activities. Practical Applications: Echinacea, which is a medicinal and aromatic plant, has been used for traditional medicine in many countries. The water extract of Echinacea purpurea (L.) Moench and Echinacea pallida (Nutt.) Nutt. exhibited excellent antioxidant activities; therefore, these Echinacea species can be used as natural agents in food and pharmaceutical industries.