Sprayers used in greenhouse have poor atomization performance with low efficiency of pesticides and workers were poisoned badly, as a result, a fixed pipes cold fogging system was designed. In order to evaluate the performance of the fogging system, a comparison test between the system and trolley sprayer was carried out, meanwhile, peppers in fruiting period were chosen to explore the influence of crop canopy on droplet distribution of fogging system. In the test, the air pressure of fogging system was 0.3MPa, the hydraulic pressure was 0.05MPa, and the application rate was 2L/min. The trolley sprayer was placed at a distance of 2m from the front collection area, in the middle of the greenhouse, and the air cylinder and the horizontal ground had an angle of 15°, spraying forward, the application rate was 1.5L/min. The total application time was 5min. The results showed that different from the trolley sprayer, the droplet deposition coefficient of variation of fogging system among different collection areas was only 13%, indicating that the fogging system can achieve unmanned pesticide application throughout the greenhouse with good uniformity of droplet distribution;the presence of peppers in the greenhouse was conducive to droplets gather on surrounding leaves, droplet deposition in the vertical height in different regions had no significant difference, with coefficient of variation no more than 13%. In summary, the fogging system had stable working performance and uniform droplet distribution, obviously improving the control efficiency of pests and diseases, realizing the separation work between human and the fogging system, having wide prospect in application.