The present invention discloses an enhanced membrane for battery isolation, which is a biaxially-oriented expanded polytetrafluoroethylene microfiltration membrane, with a longitudinal tensile strength of 25 to 30 Mpa, a transverse tensile strength of 20 to 25 MPa, a longitudinal elastic modulus of 70 to 80 Mpa, a transverse elastic modulus of 50 to 60 Mpa, and a maximum longitudinal and transverse force of 3 to 4 N. The present invention also discloses a method of manufacturing an enhanced membrane for battery isolation, which comprises the steps of mixing-pressing-extruding-rolling-removing the lubricant-longitudinally stretching -heat treatment-cooling and shaping-transversely stretching-thermally shaping-cooling and shaping. The present invention has better dimensional stability and higher mechanical performance, and can significantly reduce the internal resistance of batteries and improve the performance of batteries, reduce the consumption of membrane materials, reduce the cost, and thus have a wide range of application.