The marine ecosystem is very complicated

so it is impossible to cultivate all kinds of the microorganism in deep sea.To improve the precision of marine microbial detection and reduce the measuring error

an automatic on-line measurement system is needed.Based on the ATP bioluminescence reaction detection principle

a design scheme of in-situ detecting system for marine microorganism amount is presented.The equipment uses C8051F as the microprocessor

integrates A/D conversion

electromagnetic valve and stepper motor drive modules

achieves fully automatic operation.The working principle of the system is described and the system components are introduced.The experimental result shows that this system can work well

and the measurement error is small

the precision can reach ±7 % when measuring 10-9mol/L scalar standard ATP solution.The in-situ and on-line detection for microorganism is realized.