The invention discloses a multi-segment reactor for pyrolyzing carbon material by plasma. The multi-segment reactor for pyrolyzing carbon material by plasma comprises a first reaction tube segment, second to Nth reaction tube segments, at least one carbon material and carrier gas inlet, at least one first heating gas inlet, at least one second to Nth heating gas inlet, at least one inlet for chilling medium, and at least one chilling product and gas outlet. The first reaction tube segment is mainly used for mixing the carbon material, carrier gas and first heating as and pyrolyzing the carbon material. The second to Nth reaction tube segments are mainly used for gas-phase reaction of volatiles produced in pyrolysis, and N is an integer not smaller than 2. The carbon material and carrier gas inlets are located at the top of the first reaction tube segment. The first heating gas inlets are located on the lateral side of the first reaction tube segment. The second to Nth heating gas inlets are located on the lateral sides of the second to Nth reaction tube segments respectively. Second to Nth heating gases are high-temperature plasma gases. The chilling medium is used for chilling or freezing reaction products. The chilling product and gas outlets are located at the bottom or on the lower portion of a reaction tube.