The invention relates to a set of high-concentration liquid carbon dioxide capture system and method, wherein the method is characterized by mainly including five parts: filtration, compression, purification, liquefaction and rectification. The method comprises the steps: carrying out gas-liquid separation of carbon dioxide mixed gas produced from coal gasification by a filter, compressing by a gas compressor, allowing the product to enter a purifier and a fine purifier, carrying out further removal of impurities, to obtain relatively pure carbon dioxide gas, at the same time, discharging non-carbon dioxide gas into an oil recovery device and a sulfide filter, and recovering purified oil gas products and sulfide; followed by, allowing a gas flow to enter a liquefaction zone through a pipeline, carrying out heat exchange, after liquefaction, outputting liquid carbon dioxide, and carrying out rectification purification of liquid carbon dioxide by a carbon dioxide rectification tower forseparating other impurities in the liquid carbon dioxide; and finally, further cooling by a cryogenic device, outputting liquid carbon dioxide, and storing, so as to realize the purpose of capture ofthe high-concentration liquid carbon dioxide.