The invention discloses a removal technology of removing coal-fired flue gas pollutants and a device thereof. The technology is as follows: an SCR denitration method is first used for removing NOX in the flue gas; then a dust collector is used for removing dusts and ash particles in the flue gas; then a wet calcium-based desulphurization method is used for removing SO2 in the flue gas; then an MEA decarburization process is used for absorbing the SO2 in the flue gas; simultaneously, a pregnant solution of a generated alkanolamine solution is heated, analyzed and regenerated and the generated barren solution of the alkanolamine solution is continuously and cyclically used; and the analyzed CO2 gas with high concentration is produced to be liquid carbon dioxide of industrial grade with high purity after being cooled, gas-liquid separated, dried, compressed and condensed. The device consists essentially of an SCR denitration reactor, the dust collector, a wet calcium-based desulphurization reactor, an MEA decarburization absorption tower, a regeneration tower, a gas-liquid separator, a dryer, a compressor, a condenser and the like which are connected with each other by pipes. The device has simple and compact overall design, low investment and operation costs, and stable and reliable work and can conduct classified integration processing and highly efficient simultaneous removal on every pollutant in the coal-fired flue gas.