Aiming at the processing of the valve sleeve of the highprecision thinwalled hydraulic reversing valve made of 38CrMoAl material,difficulties in turning process were analyzed and reasonable processing methods were formulated,according to the characteristics of material,heat treatment and the unique structure.By means of common numerical control machines,external grinding machine and internal grinding machine,and by improving the process of turning and grinding,optimizing the workpiece installation,the cylindricity of inner hole gets to 0.004 mm and the coaxiality of excircle gets to 0.02 mm,which meets the design requirements.The quality of product maintains stable in small batch productions，and the percent of pass is over 92%.It provides the beneficial reference for this type of precision hydraulic valve parts.