The invention discloses a 
polishing method for rotating an 
abrasive stream of an entire 
impeller part. The 
polishing method is characterized by comprising the following steps of: firstly, protecting non-polished faces, such as upper and lower end faces of an 
impeller and outer edges of blades, by virtue of a special shape clamp cover, and integrally fixing with a workpiece; secondly, properly buffering and adjusting before the workpiece is polished by 
abrasive through an 
abrasive stream drainage device, so that a pressure field in a sealing cavity is uniformly distributed; thirdly, driving an equipment spindle and the workpiece to rotate by using a power 
system consisting of a motor and a speed 
reducer; and finally, converting to a high-pressure water cleaning 
system to wash the workpiece and an equipment pipeline after 
polishing. According to the polishing method provided by the invention, the problems in a polishing process of the entire 
impeller part of easiness of interference, excessive polished blades, chamfering, dead angle and uniform polishing can be solved; the abrasive circularly flows in double directions so as to be easy to recycle; the 
machining efficiency is improved; and clean-in and clean-out in a 
machining process can be realized through the 
water washing system after the polishing process.