Abstract: The type, character, selection and appraise criterion about common, corrective and hybrid profile of scroll compressor are introduced. Some theories of the common profile are summarized and the content, the substance and studying value are brought to light. Some theories of the general profile are corrected and extended. It is not only correct some mistakes of old theory about the general profile, but also perfect the theories. The dimensionless of the theory of the general profile has contribute to decrease the affect of the dimension parameters and will be easy to made the contract with different designing programmers. It has contribute to select the profile type using the pattern detected method. A new index to appraise the profile——error senitiveness of the profile is bring forward. It shows some relationship between the mesh clearance and the profile equation. Lastly, The scale transform and approaching methods of the profile are introduced. The method made it possibility to approach the scroll profile by high order polynomial and study the profile in different scale dimension.

Key words: Compressor scroll, Failure of liquid film, Profile