Abstract: The present invention provides a positioning assembly for a gripping tube of a handlebar. The positioning assembly comprises a gripping tube sheathing the handlebar, wherein each of two ends of the gripping tube is positioned by a fastening ring, which has an annular shape, a slit, an outer ring periphery and an inner ring periphery. Therein, a prominence radially raised and two increased-thickness portions are provided on the inner ring periphery so that when the slit of the fastening ring is narrowed, the fastening ring can tightly embrace an outer surface of the handlebar with the prominence and the two increased-thickness portions.