In order to increase an areal density, femto slider has been used in this system nowadays. When the design parameters are changed a little due to fabrication, assembly error and operating conditions, the L/UL dynamic characteristics of femto slider can be changed greatly. This paper investigates the static air bearing characteristics of two sliders which have a different ABS. L/UL dynamic performance is examined using the numerical simulation for various design and operating parameters. For the same suspension parameters and operating conditions, L/UL dynamics show the different characteristics for different ABS system. In case of femto slider used in this simulation, the rebounding happens in a lower load speed and the simulation results shows the clearance between slider and disk become small in unloading process.