Abstract: The feature of ultrafiltration to remove particle matters is introduced in this article.It is pointed that particle contents are key monitoring and control index to ensure treated water quality of membrane filtration.Particle monitoring techniques are briefly illustrated and the application features are analyzed with several particle monitoring techniques.Correlations of turbidity,particle counting value,multiple index of particle and microbe index are studied and analyzed.The results show that particle number is the key monitoring indicator of treated water quality of ultrafiltration.It is suggested that the particle index can be applied to replacing or replenishing turbidity index,and particle monitors can be utilized to replace or replenish turbidity meters to monitor and control operation of ultrafiltration equipment in practical applications,in order to provide safety to effective operation of ultrafiltration and production of high-quality water.