The invention discloses a refuse pyrolysis comprehensive sewage treatment system and method. The system comprises a refuse percolate collection tank, a grid, a hoisting shaft, a refuse pyrolysis sewage collection tank, a first adjusting tank, an air flotation tank, a second adjusting tank, a biochemical tank, an activated carbon adsorption tank and a clean water tank, the grid is connected with the refuse percolate collection tank, the hoisting shaft is connected with the grid, the first adjusting tank is connected with the refuse pyrolysis sewage collection tank, the air flotation tank is connected with the first adjusting tank and provided with a demulsifier feeding port and an oil sludge discharging port, the second adjusting tank is connected with both the hoisting shaft and the air flotation tank and provided with a stirring device, the biochemical tank is connected with the second adjusting tank and provided with a concentrate outlet, the activated carbon adsorption tank is connected with the biochemical tank, and the clean water tank is connected with the activated carbon adsorption tank. By adopting the system, treatment of refuse pyrolysis sewage and refuse percolate at the same time is realized, outgoing water reaches standards, energy conservation and emission reduction are realized, and the system has engineering application value.