The invention discloses a micro oxygen rich combustion W flame boiler and a CO2 emission reduction system, which is characterized in that anthracite or low-volatile coal is introduced in the W flame boiler furnace for fully combusting, the formed flue gas is divided into two strands through a heat exchange zone and a gas-gas heat exchanger after cooling, one strand is taken as a recycling flue gas; air and oxygen are simultaneously heated in the gas-gas heat exchanger, the heated air is divided into three strands, oxygen is divided into two strands, a first strand of oxygen and a first strand of air are mixed and introduced in a furnace arch primary air pipeline, a second strand of oxygen and a second strand of air are mixed and introduced in a furnace arch secondary air pipeline, and a third air is introduced in a back and forth wall secondary air pipeline. The invention combines the micro oxygen rich combustion technology and the W flame boiler, the desulphurization, denitration and capture with lower cost can be realized, and zero discharge can be realized. The pure oxygen amount required by fuel combustion with unit mass under a micro oxygen rich combustion mode is obviously reduced by comparing with oxygen rich combustion, and energy consumption and cost of air separation oxygen preparation can be greatly reduced.