A pure counterflow lamella heat exchanger with the gas-liquid separation function comprises a shell and a heat exchange plate bundle, wherein the heat exchange plate bundle is installed in the shell. Atomizers are arranged in the space between the shell and the heat exchange plate bundle. A separator is arranged at the cold medium input end in the shell. A hot medium flow-in connecting pipe and a cold medium flow-in connecting pipe are arranged on an upper end socket and a lower end socket of the shell respectively, and a cold medium flow-out connecting pipe and a hot medium flow-out connecting pipe are arranged on the upper portion and the lower portion of the shell respectively. Heat exchange, purification and separation of media are all finished in the same shell, and therefore the pure counterflow lamella heat exchanger is compact in structure, internal space and structural advantages of the lamella heat exchanger are fully utilized, gas heat exchange and gas-liquid separation and purification are organically combined together, purification treatment of heat exchange gas can be achieved on a single shell on original heat exchanger equipment under the condition that equipment is not additionally arranged.