A real-time online analysis device for substance pyrolysis, characterized in that , the device comprises: a pyrolyzing system , a capturing system , a testing system and a controlling system ; wherein: the pyrolyzing system , the capturing system and the testing system are connected with the controlling system ; the capturing system has a cooling cavity and a heating cavity inside, temperature of the cooling cavity ranges from room temperature to -200°C, and temperature of the heating cavity ranges from room temperature to 1000°C; and wherein the capturing system comprises the following components: A horizontal moving slot ; A cooling cavity , arranged at one end of the horizontal moving slot ; The cooling cavity has a cooling tube , which is connected with a cooling gas device ; the cooling cavity is in airtight connection with the pyrolyzing system through a gas pipeline ; A heating cavity , arranged at the other end of the horizontal moving slot ; the heating cavity has a heating tube ; the heating cavity is in airtight connection with the testing system through the gas pipeline ; A rotary collector arranged on a horizontal moving slot between the cooling cavity and the heating cavity , which can slide along the horizontal moving slot towards the cooling cavity or the heating cavity ; a plurality of collecting tubes are provided on a rotary collector , and the plurality of collecting tubes are arranged on the radius of the rotary collector ; A purging gas pipe connected to the rotary collector . the pyrolyzing system , the capturing system and the testing system are connected with the controlling system ; the capturing system has a cooling cavity and a heating cavity inside, temperature of the cooling cavity ranges from room temperature to -200°C, and temperature of the heating cavity ranges from room temperature to 1000°C; and wherein the capturing system comprises the following components: A horizontal moving slot ; A cooling cavity , arranged at one end of the horizontal moving slot ; A horizontal moving slot ; A cooling cavity , arranged at one end of the horizontal moving slot ; The cooling cavity has a cooling tube , which is connected with a cooling gas device ; the cooling cavity is in airtight connection with the pyrolyzing system through a gas pipeline ; A heating cavity , arranged at the other end of the horizontal moving slot ; the heating cavity has a heating tube ; the heating cavity is in airtight connection with the testing system through the gas pipeline ; A rotary collector arranged on a horizontal moving slot between the cooling cavity and the heating cavity , which can slide along the horizontal moving slot towards the cooling cavity or the heating cavity ; a plurality of collecting tubes are provided on a rotary collector , and the plurality of collecting tubes are arranged on the radius of the rotary collector ; A heating cavity , arranged at the other end of the horizontal moving slot ; the heating cavity has a heating tube ; the heating cavity is in airtight connection with the testing system through the gas pipeline ; A rotary collector arranged on a horizontal moving slot between the cooling cavity and the heating cavity , which can slide along the horizontal moving slot towards the cooling cavity or the heating cavity ; a plurality of collecting tubes are provided on a rotary collector , and the plurality of collecting tubes are arranged on the radius of the rotary collector ; A purging gas pipe connected to the rotary collector . <EOS>