Fecal E. coli is derived from the intestines of people and other warm blood animals and is discharged through feces. The survival time of fecal E. coli in natural environment is the closest to the pathogen, and the number of fecal E. Therefore, the content of fecal E. The time of fecal E. coli survival in water, the resistance to disinfectant and adverse factors in water are similar to pathogenic bacteria. In practice, fecal E.coli is often used as indicator to evaluate the water quality. The online monitoring system of fecal E. coli is a multi parameter microorganism online monitoring product based on the technology of enzyme substrate microbial detection. It is the first time that the laboratory enzyme substrate microbial detection technology is applied to the on-line automatic monitoring of water quality on site, which fills in the blank at home and abroad. The product can detect the total number of colonies, total fecal E.coli, heat-resistant (fecal) fecal E.coli and Escherichia coli in surface water, groundwater, sea water and drinking water, and can be combined arbitrarily. The concept of single field water quality monitoring instrument is broken through, and a multi-purpose and arbitrary combination of the laboratory platform for on-site water quality automatic monitoring is built. Enzyme substrate microbial detection technology has the advantage of rapid online automatic detection, and it can realize on-line culture detection of many kinds of microorganisms in 6-18 hours. This product is suitable for: hospital sewage, drinking water source, surface water quality automatic monitoring station, sewage treatment plant outlet, etc.