A sample pretreatment method of micro-extraction tube injection, comprising: providing a capillary micro-extraction tube with extracting medium in it as an injector, passing a sample through the capillary micro-extraction tube, during which an analyte is extracted into the extracting medium inside the capillary micro-extraction tube; then, filling the capillary micro-extraction tube with an organic solvent and keeping the filling for a certain period of time, so that the extracted analyte is dissolved in the organic solvent inside the capillary micro-extraction tube to form an injection solution; and finally, keeping one end of the capillary micro-extraction tube sealed and inserting the open end directly into an injection port of a gas chromatograph, such that the injection solution is automatically ejected out from the capillary micro-extraction tube into the injection port to complete the injection operation for gas chromatography; the sample pretreatment method comprising: preparing a micro-extraction injector from the capillary micro-extraction tube by tightly connecting the micro-extraction injector with a barrel of a syringe; activating the capillary micro-extraction tube by passing an activation liquid through the capillary micro-extraction tube by the aid of a syringe pump; loading a sample solution by passing the sample solution through the capillary micro-extraction tube at a certain flow rate by the aid of a syringe pump; washing the capillary micro-extraction tube by passing a cleaning liquid through the capillary micro-extraction tube by the aid of a syringe pump, and removing water inside the capillary micro-extraction tube as much as possible by passing air through the capillary micro-extraction tube; filling the capillary micro-extraction tube fully with the organic solvent using a syringe pump, sealing the two ends of the capillary micro-extraction tube with a silicone septum at each end, and standing for a period of time, so that the extracted analyte is dissolved in the organic solvent to form the injection solution; and finally, opening one end of the capillary micro-extraction tube by taking down the silicone septum thereof, keeping the other end sealed, and inserting the open end directly into the injection port of the gas chromatograph, such that the injection solution is automatically ejected out from the capillary micro-extraction tube into the injection port to complete the sample injection operation. providing a capillary micro-extraction tube with extracting medium in it as an injector, passing a sample through the capillary micro-extraction tube, during which an analyte is extracted into the extracting medium inside the capillary micro-extraction tube; then, filling the capillary micro-extraction tube with an organic solvent and keeping the filling for a certain period of time, so that the extracted analyte is dissolved in the organic solvent inside the capillary micro-extraction tube to form an injection solution; and finally, keeping one end of the capillary micro-extraction tube sealed and inserting the open end directly into an injection port of a gas chromatograph, preparing a micro-extraction injector from the capillary micro-extraction tube by tightly connecting the micro-extraction injector with a barrel of a syringe; activating the capillary micro-extraction tube by passing an activation liquid through the capillary micro-extraction tube by the aid of a syringe pump; loading a sample solution by passing the sample solution through the capillary micro-extraction tube at a certain flow rate by the aid of a syringe pump; washing the capillary micro-extraction tube by passing a cleaning liquid through the capillary micro-extraction tube by the aid of a syringe pump, and removing water inside the capillary micro-extraction tube as much as possible by passing air through the capillary micro-extraction tube; filling the capillary micro-extraction tube fully with the organic solvent using a syringe pump, sealing the two ends of the capillary micro-extraction tube with a silicone septum at each end, and standing for a period of time, so that the extracted analyte is dissolved in the organic solvent to form the injection solution; and finally, opening one end of the capillary micro-extraction tube by taking down the silicone septum thereof, keeping the other end sealed, and inserting the open end directly into the injection port of the gas chromatograph, such that the injection solution is automatically ejected out from the capillary micro-extraction tube into the injection port to complete the sample injection operation.