Abstract: In order to study the performance of the rotatingcage spraying atomizer of biological pesticide.Firstly, the atomizing principle of cage, and the optimal range of the droplet diameter were proposed theoretically. Secondly, the experiment of normal temperature water and biological pesticide white muscardine fungi was performed along with the change of the mesh number, cage diameter, flow rate, motor rotational speed and the spraying pressure, the achieved atomization effect was analyzed. The results showed that the diameter of the droplet was about 100 μm and the activity of biological pesticide was up to 75 %.The farther collected location was, the bigger droplet diameter was and the lower activity was. The diameter of droplet increased firstly and then decreased with the increase of the rotating velocity，mesh number and the cage diameter, but there was no impact on the activity. The larger pressure was, the lower activity was.