The invention discloses an electrochemical 
microorganism autotrophic 
nitrogen removal 
sewage treatment method and 
system. The 
system comprises a 
microorganism electrolytic tank shell, a sealed cover, a 
microorganism positive 
electrode, a microorganism negative 
electrode and a power supply, wherein the sealed cover covers the microorganism electrolytic tank shell to form a 
closed space; the microorganism positive 
electrode and the microorganism negative electrode are connected with a negative electrode and a positive electrode of the power supply respectively, a short-distance 
nitrification microorganisms are enriched on the microorganism positive electrode, and 
denitrification methane anaerobic oxidation microorganisms are enriched on the microorganism negative electrode; the side, close to the microorganism positive electrode, of the microorganism electrolytic tank shell is provided with a water inlet, and the side, close to the microorganism negative electrode, of the microorganism electrolytic tank shell is provided with a water outlet. An inorganic 
carbon source put-in opening is formed in the position, close to the microorganism negative electrode, between the microorganism positive electrode and the microorganism negative electrode. By means of one electrolytic tank, short-distance 
nitrification, electrochemical 
methane production and 
methane anaerobic oxidation are effectively coupled, reaction 
mass transfer efficiency is accelerated, occupied area is small, and capital construction investment is small.