With the rapid development of numerical control technology, complex, high-speed, intelligent, sophisticated, green "has become the main trend of the Machine Tool Industry and Technology Development. Among them, high-speed processing can effectively improve the machining efficiency, shorten the processing cycle of the work piece, which requires the machine spindle and its associated components to adapt to the requirements of high-speed processing. Similarly, high-precision high-speed CNC machining center spindle assembly, the feed part of the precision bearings must meet the high precision of machine tools, high speed, low noise, trouble-free, high-reliability requirements. Precision bearings directly affect the quality of the assembly to its working condition and service life, CNC machining center, the failure is caused by improper assembly of the bearing, and precision bearing assembly technology should be given enough attention. Now high-speed precision bearings assembly main points are summarized as below. Removal and cleaning of precision bearings keep hands clean and dry precision bearings out of a box, the operator's hands should be kept clean and dry, because the sweat of the hands will lead to rust, if necessary, wear gloves. (2) to ensure precision bearings should be removed by the good lubricating effect immediately loaded grease and oiled treatment fat liquoring precision bearings immediately after removing the pollution-free installation, no loaded grease and oiling. In the cage and the bearing outer ring gap must be installed fat, 20% of precision bearings and grease to the cavity 30% better, high-speed precision bearings and grease cavity. Packaging sealed precision bearings can only be removed from the original packaging in the assembly before cleaning. Which sets out of the multi-precision bearings sealed from the volatile corrosion inhibitor packaging seal, VIC paper protective gas can only be maintained in the sealed packaging? The correct cleaning fat precision bearings before assembly can not clean, without added fat precision bearings must be cleaned before assembly after cleaning should be dried and immediately on the anti-rust oil or the installation of grease to prevent corrosion. Precision bearings to grease and cleaning can be used cleaning agent: aqueous cleaning agent - neutral, acidic or alkaline cleaning agents, cleaning before check alkaline cleaning agents and aluminum parts compatibility; organic cleaning agents - acid and anhydrous kerosene, benzene (non-car with gasoline), Freon 12 substitutes or chlorinated hydrocarbon cleaning agent. Precision bearing cleaning is important to note the following: environmental protection, health and job security; cleaning agents, methods of operation must comply with product descriptions, to avoid danger.