Abstract Single crystal germanium has good physical property and is widely used, but it is hard to process the surface of single crystal germanium by traditional processing technology. Although using two-phrase flow polishing technology can make effective processing on the surface of single crystal germanium, but it could also cause edge abrasion as well. The paper was based on two-phrase flow polishing theory, which built a flow-path simulation model based on the location relationship of each part of polishing machine, used Fluent to simulate the polishing process and designed experiment to analyse the polishing process. By simulation and experimental analysis we can find that, during the polishing process, the liquid-solid two-phrase flow would cause edge abrasion of test-piece, but the abrasion degree on each side of the test-piece is different. The difference of pressure which caused by liquid flow and the change of flow-path size are the main reasons of edge abrasion. Under existing processing conditions, using diamond abrasive could get higher surface accuracy, but the edge abrasion of the specimen is obvious. To reduce the edge abrasion, larger size of abrasive should be used.