Disclosed in this invention is a method for improving tear resistance of stretch films in which two stretch films are bonded together with an adhesive by hot rolling or UV curing such that their primary stretch directions cross each other. Composite films resulting from the invention possess significantly improved slit tear strength and tear resistance over biaxially stretched films with the same thicknesses. The invention can be widely used to improve tear resistance of stretch films fabricated from various existing materials and processes. In addition, it allows simple operations and is readily applicable to mass production.