Objective To assess the mosquito-killing effect of ultra-low-volume spraying machine during night and day in community and Zhongshan Park at Shaoguan, and provide the scientific basis to choose scientific and effective mosquito-killing technology. Methods Used the large vehicle-mounted ultra-low-volume machine spraying pesticide to kill mosquitoes in Shaoguan communities and park environment, respectively during night and day, then evaluated mosquito-killing effect of applying pesticide spray during night and day by Mosq-ovitrap positive index (MOI) and human-bait of monitoring Aedes density before and after applying pesticide. Results After ultra-low-volume spraying during night and day respectively at villa of Shaoguan Country Garden, human-bait index was reduced by 98.19% and 76.85%, MOI by 81.15% and 43.86%; at park, human-bait fell by 76.47% and 77.78% respectively, and MOI fell by -58.54% and 76.33% respectively. Human-bait relative density index of nighttime, daytime spraying at villa was 3.90 and 14.25 respectively, MOI was 38.48 and 24.47; human-bait relative density index at park was 33.82 and 44.44, MOI was 99.09 and 45.68. Conclusion The ultra-low-volume spraying in Shaoguan community environment at nighttime was significantly better than daytime spraying, but in Zhongshan Park the results were similar. In community environment, nighttime ultra-low-volume spraying, compared with spraying during the day, can effectively kill mosquitoes and keep mosquito-borne diseases at low density level, and has a certain application prospect.