The supervision and determination of the mass concentration and size of the particulate matters in different industrial emissions are one of the most important problems faced now in China and in other countries. Several methods have been used for this purpose for a long time. Nevertheless, they can not meet all the modem requirements in environment control and give satisfactory results of measurements. In this paper, based on the light scattering theory, a novel method is presented, which is capable to make real time and on-line measurement of the mass concentration as well as the size of particulate matters in different industrial emissions. Theoretical analysis, computer simulation and experimental investigations are given and discussed.