The invention provides an autotrophic 
denitrification deep 
denitrification device, and belongs to the technical field of 
wastewater deep 
denitrification. The device comprises an adjusting tank, a reactor and a 
sedimentation tank; a 
sludge discharge area is arranged at the bottom end in the reactor; a water distribution 
pipe is arranged above the 
sludge discharge area; a filter screen is arranged between the 
sludge discharge area and the water distribution 
pipe; a reaction area is arranged on the water distribution 
pipe; and a gas collection area is arranged above the reaction area. According to the device, an autotrophic denitrification 
biological filter bed is constructed, and types and proportions of fillers in the reaction area are optimized. The invention also discloses an autotrophicdenitrification deep denitrification method. The method optimizes the 
operation mode and operation condition and improves 
biological activity and denitrification capacity of autotrophic denitrification 
bacteria in a 
system, so that the starting time is shortened, and the denitrification effect of the 
system is enhanced. The autotrophic denitrification deep denitrification device has the characteristics of low 
energy consumption, quick reaction, no secondary 
pollution and the like, and solves the problems of long starting time, high 
sulfate radical concentration of outlet water, easy blockage,easy 
sulfur outflow and the like of an existing autotrophic denitrification technology in a process of treating low-carbon-source 
sewage.