Abstract: By way of overcoming mechanism structure factors seriously affecting on performance of opto-electronic tracker servo systems, the relationship between servo system performance and servo mechanism structure factors that consist of inertia moment,structure resonance frequency and friction moment is analyzed. These include relations between inertia moment and servo system performance, between structure resonance frequency and servo system performance, and between friction moment and servo system performance. The measures that avoid or minimize the mechanism resonance are probed. These analytical methods may be used to design and make the opto-electronic tracker servo systems with quick response and high tracking accuracy.