The invention provides a preparation method of an air filtering 
nanofiber membrane with a dendritic multilevel structure. The preparation method of the air filtering 
nanofiber membrane with the dendritic multilevel structure comprises the following steps of adding amino-terminated hyperbranched 
quaternary ammonium salt into a 
dimethylacetamide / 
acetone compound organic solvent system of 
polyvinylidene fluoride, magnetically stirring at a certain temperature to prepare a homogeneous 
spinning solution, and then preparing through electrostatic 
spinning. According to the preparation method of the air filtering 
nanofiber membrane with the dendritic multilevel structure provided by the invention, on the basis of the principle that electrostatic 
spinning jet flow can be split, the amino-terminated hyperbranched 
polymer quaternary ammonium salt with a highly branched three-dimensional structure and excellent 
antibacterial property is added into a spinning solution, splitting of spinning 
jet flow is promoted through increase of the 
conductivity of the spinning solution and the steric hindrance effect, and the air filtering nanofiber membrane with abundant dendritic multilevel structures is prepared by adopting an electrostatic spinning technology and a one-
step method. According to the preparation method of the air filtering nanofiber membrane with the dendritic multilevel structure provided by the invention, the preparation process is simple, the dendritic structure coverage rate is high, the filtering performance is good, the antibacterial performance is excellent, and the application prospect is good.