Micro-whirling Reactor which is the new technology of coagulation and it s working mechanism are illustrated in the paper,and its application in hydraulic circulating clarifier in south city water supply plant of Jimo water supply company is introduced.

This paper expounds the working principles of hydraulic circulating clarifier and the present situation of its application, and in the light of its existing disadvantages such as high energy consumption, over-short reaction time, low and unstable running efficiency, difficult control of sludge reflux, and little output, etc.