Abstract：The mass line is the starting point of maintaining CPC's purity and its final goal as well. To maintain CPC 's purity, CPC officials and members should strengthen the education of Marxism mass viewpoint and mass line, improve abilities to perform the mass work well under new conditions, broaden channels and establish systems of communicating with and serving the mass, perfect the mechanism of surveillance and evaluation by the mass. In a word, CPC's purity should be achieved in upholding and developing the guideline of mass line.

Keyword：upholding and developing;the mass line;CPC's purity;