Abstract: Abrasive wear experiment of PEN(polyethylene2, 6-naphthalenedicarboxylate) tape was performed in sand dust environment with ATM(Auto Teller Machine) tribosystem.Worn profiles of PEN tape with different wear duration were measured with definite interval by using surface profiler.Fractal parameters including fractal dimension and character length of worn surface profile were calculated with construction function method and corresponding wear mechanisms were examined by SEM.It is suggested that worn surface of PEN tape by sand dust particles showed bi-fractal characteristics.Ploughing and cutting by sand particles and micro-fracture were found to be the two main mechanisms for each fractal characteristics in large and small scale.