The production of a well-formed nonwovens sheet by the wet-laid process requires separating the fiber bundles into individual fibers in water. Producing a well-formed sheet in the wet laid process often requires the use of both a dispersant and a formation aid. It has generally been recognized that glass fibers can be dispersed in strong acid condition or by chemical treatment. However the use of chemicals or chemical treatments causes serious environmental pollution. To overcome this, in this study we examined whether glass fibers are well dispersed or not by ultrasonic system alone without using any dispersants or acids. And we have experimentally evaluated the effects of aspect ratio of the fiber and mixing time in water. We also examined the tensile strength of webs to confirm the directional properties of the fiber webs. The experimental results reveal that the dispersibility of glass fibers in water is poor with increasing aspect ratio, and mixing time.