The particle size distribution of nebulizer is an important index to evaluate the performance and therapeutic effect of nebulizer. The laser diffraction particle size analyzer with Mie scattering algorithm was used to research the influence of different compression nebulizer, nebulization cups, detection carriers and detection environments on the size distribution of particles. The experiment showed that: under the same detection environment and conditions, the output flow rate of the compressed nebulizer is positively correlated with the particle size distribution and proportion, and inversely correlated with the particle size under the same size distribution and proportion; the use of matching nebulization cup can ensure the effective particle concentration distribution; according to different carriers, only by reasonably setting the particle size distribution and proportion parameters, can the performance test of atomizer be comparable. In order to avoid the interference of the external light environment, the detection should be carried out under the condition of no external light as far as possible， so that the obtained data can be reliable.