In order to enhance the machining precision of titanium alloy thin-walled cylinders,two Ti-6Al-4V thin-walled cylinders with different structures were prepared by using hot isostatic pressing technology.The influences of the fixture,poured slurry and cylinder structure on the cylindrical surface roughness and cylindrical precision were studied.The results show that hot isostatic pressing Ti-6Al-4V thin-walled cylinders after machining can reach the accuracy requirements,poured slurry can reduce elastic spring back to improve outer ring precision of the thin-walled cylinders;the inner ring and thick end of the cylinder structure can enhance stiffness to reduce the cylindrical surface roughness effectively;while big fixture layout error can make a significant influence on roundness and coaxiality,the large error remarkably decreases the outer ring precision.