Affected by COVID-19, disinfection and purification in public space, such as ordinary school, had aroused wide public concern. This study presents an improved structure of nowadays medical used UV air purifier and discusses about its efficiency optimization, by utilizing following processes: Firstly, establishing the inner structure of the machine on computer and setting up the boundary conditions. Secondly, employing CFD (Computational Fluid Dynamics) to proceed the simulation of air swirl and the time used, and analyzing the relationship between different parameters and time. Finally, combining optimized parameters to obtain the best time used. The optimized structure efficaciously reduces the cost of machine, making utilization in the classroom become possible.