A sample injector, comprising a sample injector shell and a vaporizing chamber located in the sample injector shell, wherein: a sample injector shell opening and a detachable end cover are arranged at the top of the sample injector shell, and the end cover seals the sample injector shell opening; a vaporizing chamber opening is arranged at the top of the vaporizing chamber, and a channel for enabling a gas to pass is reserved between the vaporizing chamber opening and the end cover; a carrier gas channel, a septum purge channel and a coolant channel are further arranged in the sample injector shell along the outer circumference of the vaporizing chamber, a carrier gas channel opening portion and a septum purge channel opening portion are respectively arranged at the tops of the carrier gas channel, the coolant channel and the septum purge channel, and both of the carrier gas channel opening portion and the septum purge channel opening portion communicate with the opening at the top of the vaporizing chamber; the carrier gas channel is provided with a carrier gas inlet, the septum purge channel is provided with a septum purge channel outlet, and the coolant channel is provided with a coolant inlet and a coolant outlet; a capillary column is arranged at the bottom of the vaporizing chamber, one end of the capillary column projecting into the vaporizing chamber, and the other end of the capillary column projecting out of the sample injector; a heater is further arranged in the sample injector shell, said sample injector being characterized in that: the heaters are uniformly distributed on the outer wall of the sample injector shell, a temperature control unit is further comprised, and the heaters are controlled by the temperature control unit to achieve single-point temperature heating or programmed temperature heating, the inlet of the carrier gas channel, the outlet of the septum purge channel and the inlet and the outlet of the coolant channel (10, 17) are all connected with the gas flow control valve, and the temperature control unit is further connected with the gas flow control valve; the temperature control unit and the gas flow control valve cooperate to cool the sample injector. a sample injector shell opening and a detachable end cover are arranged at the top of the sample injector shell, and the end cover seals the sample injector shell opening; a vaporizing chamber opening is arranged at the top of the vaporizing chamber, and a channel for enabling a gas to pass is reserved between the vaporizing chamber opening and the end cover; a carrier gas channel, a septum purge channel and a coolant channel are further arranged in the sample injector shell along the outer circumference of the vaporizing chamber, a carrier gas channel opening portion and a septum purge channel opening portion are respectively arranged at the tops of the carrier gas channel, the coolant channel and the septum purge channel, and both of the carrier gas channel opening portion and the septum purge channel opening portion communicate with the opening at the top of the vaporizing chamber; the carrier gas channel is provided with a carrier gas inlet, the septum purge channel is provided with a septum purge channel outlet, and the coolant channel is provided with a coolant inlet and a coolant outlet; a capillary column is arranged at the bottom of the vaporizing chamber, one end of the capillary column projecting into the vaporizing chamber, and the other end of the capillary column projecting out of the sample injector; a heater is further arranged in the sample injector shell, said sample injector being characterized in that: the heaters are uniformly distributed on the outer wall of the sample injector shell, a temperature control unit is further comprised, and the heaters are controlled by the temperature control unit to achieve single-point temperature heating or programmed temperature heating, the inlet of the carrier gas channel, the outlet of the septum purge channel and the inlet and the outlet of the coolant channel (10, 17) are all connected with the gas flow control valve, and the temperature control unit is further connected with the gas flow control valve; the temperature control unit and the gas flow control valve cooperate to cool the sample injector. the heaters are uniformly distributed on the outer wall of the sample injector shell, a temperature control unit is further comprised, and the heaters are controlled by the temperature control unit to achieve single-point temperature heating or programmed temperature heating, the inlet of the carrier gas channel, the outlet of the septum purge channel and the inlet and the outlet of the coolant channel (10, 17) are all connected with the gas flow control valve, and the temperature control unit is further connected with the gas flow control valve; the temperature control unit and the gas flow control valve cooperate to cool the sample injector.