Potential of a surface acoustic wave (SAW) linear motor had been demonstrated; high speed up to 1.5 m/s, huge output force more than 10 N, quick response and fine stepping motion down to 0.5 nm by using a 60 x 15 x 1 mm3 SAW device at 10 MHz operation frequency and 4x4 mm Si slider by experiments. Mechanical output of the SAW motor was 270 times larger that of the weight and 500 W/kg in power. The conversion efficiency from the traveling wave power to the motor mechanical output was 14 %. Now, transformation mechanism research from high frequency vibration of 10 to 100 MHz frequency range to mechanical linear motion through frictional drive is noteworthy. Contact, friction and other physical matters between a stator and slider are being studied for stable operation and much superior performance. The slider friction surface has a lot of projections to control the contact with the stator. From the experimental results, it was shown that the slider surface projection diameter has huge influence on the motor characteristics. If the total projection contacting surface areas were same, the output force, for example, varied with the projection diameter; smaller projection, for example 20 μm diameter, had superior performance than larger one. In this paper, numerical simulation of SAW motor friction drive was successfully carried out taking account the wave amplitude attenuation in propagation beneath slider projections.