The workshop test of mount drive for Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) was completed in June of 2005. Now the giant mount has just been erected on Xinglong station, and is due to test in the summer of 2006. LAMOST mount mechanism features friction drive on both axes, and oil pad is employed specifically for the azimuth. For further improving the tracking accuracy in worse surroundings some nonlinear phenomena in the drive chain have to be addressed. Moreover, external uncertainties on Xinglong site, wind buffeting in particular, could affect load variation on the drive. The control system parameters would change with time, thus eventually degrade the tracking performance. All these reasonable assumptions call for a more robust controller than conventional PID approach to cope with. This is where H Infinity controller comes in. This paper focuses on the mount drive of LAMOST by using H-Infinity technique and comparison with the PID servo. The load disturbance rejection is discussed, as well as transmission rigidity improvement is analyzed. Study and simulation are done in Matlab. The model test in our friction drive lab is presented.