Currently, dust concentration measurement technology of the coal-fired boiler is an important research. The emissions target is gradually strict. Many dust monitoring tools can't meet the needs of real-time online measurements. This paper studies the online measurement system of dust concentration based on light scattering. Taking the advantages of charge coupled device (CCD) in fast imaging of image sensor and combining with optical method, which has high sensitivity, good reproducibility, on-line measurement and other good optical characteristics, this paper introduces dust concentration measurement system. Compared with the existing concentration measurement technologies, the light scattering method has much higher accuracy than other measurement methods', and it belongs to the technology measurement that doesn't interfere with the object. The research and development system is aimed to solve the real-time monitoring of the dust concentration in coal-fired power pant and improve the level of environmental monitoring.