High speed dental drill assembly structure as shown in figure 1. It is composed of a shaft, a worm wheel, a spring clip, a spring gasket, cover, shell, rolling bearing, rubber positioning ring parts. Worm gear, bearing shaft and too surplus with overall high-speed rotation, the bearing outer ring is supported by the positioning rubber elastic ring in the shell body, a back cover and a spring circled fastening and the action of axial force is applied to the shell by positioning the ball fixed in the phone, spring chuck in the shaft hole at the other end of the clamping drill work. Dental bearing is a key component of drill components, shape size of the typical type of SRl44TZ is 3.175mm * 6.35mm * 2.38mm phi phi. Its work in the dust, wet and harsh environment, with high speed, high precision, low noise and long life requirements. Therefore, it is required that the tolerance level is P4, the speed is (3.5 ~ 4.5) * 105 r/min, and the working life is 6 months.