Abstract: Mie scattering is a generally recognized technique with brillant prospects in particle measurement,which applies to the measurement of particle size and concentration of flue-dust emitted from factories or enterprises.It has many advantages, e.g.non-contact,high-precision, real-time on-line measurement etc. It is a main technical means for research on pollutant emission. It is also a theoretical base to analyze the particle size and concentration. In this paper, several parameters of Mie scattering are calculated and its mathematical expressions are presented in detail.