The invention belongs to the technical field of ice particle gas jet and particularly discloses an ice particle gas jet assisted coal cutting and dust suppressing device and method of a coal roadway fully-mechanized tunneling machine. The ice particle gas jet assisted coal cutting and dust suppressing device of the coal roadway fully-mechanized tunneling machine comprises a tunneling system and anauxiliary coal cutting system. The tunneling system comprises a fully-mechanized tunneling machine, spray pipes and a support, wherein the spray pipes and the support are installed on the fully-mechanized tunneling machine. The auxiliary coal cutting system comprises an air compressor, gas cylinders, a water storage tank, a liquid nitrogen tank, a gas-liquid mixing cavity, an ice forming cavity and an injection cavity, wherein an air outlet of the air compressor is connected with inlets of the gas cylinders, and outlets of the gas cylinder are connected with a gas channel. An outlet of the gas channel communicates with a first channel, a second channel and a third channel through a four-way valve. An outlet of the first channel is connected with a gas inlet at the bottom of the water storage tank. The second channel is connected with an inlet of the gas-liquid mixing cavity. The third channel is connected with an injection pipe in the injection cavity. An outlet of the injection pipeis provided with an injection spray nozzle. An outlet of the liquid nitrogen tank is connected with the ice forming cavity. An outlet of the water storage tank is connected with the gas-liquid mixingcavity. The gas-liquid mixing cavity is connected with the ice forming cavity. An outlet of the ice forming cavity is connected with the injection cavity. The outlet of the injection cavity is connected with the spray pipes. The ice particle gas jet assisted coal cutting and dust suppressing device of the coal roadway fully-mechanized tunneling machine has the advantages of being simple in structure and convenient to use.