How to quickly and accurately monitor the river flow, it has been always the study object for many hydrologists. ADCP is an advanced flow test equipment. This paper analyzed the ADCP's mechanism, proposed the concept of ADCP flow generation model, analyzed the structure of ADCP flow generation model and constructed ADCP flow generation model at last. According to flow generation model developing the ADCP flow calculation program, calculated the data by this program, and the result is very similar with that by Winriver software. It confirmed that this flow generation model is correct. And it has made a good beginning of ADCP's localization.